$QLYS
Qualys Inc Stock $qlys

$qlys Overview Financials Valuation SEC Filings Company Website

2020 Q4 Form 10-K Financial Statement

#000143774921003648 Filed on February 22, 2021

Income Statement

Concept	2020 Q4	2020 Q3	2020 Q2
Revenue	$94.80M	$93.07M	$88.83M
YoY Change	11.97%	12.58%	12.54%
Cost Of Revenue	$21.22M	$20.62M	$18.89M
YoY Change	23.66%	20.52%	7.72%
Gross Profit	$73.58M	$72.45M	$69.94M
YoY Change	9.01%	10.5%	13.92%
Gross Profit Margin	77.62%	77.85%	78.73%
Selling, General & Admin	$30.53M	$28.28M	$26.37M
YoY Change	1.26%	8.3%	-4.41%
% of Gross Profit	41.49%	39.04%	37.71%
Research & Development	$18.64M	$17.86M	$18.06M
YoY Change	4.66%	5.71%	2.05%
% of Gross Profit	25.33%	24.66%	25.82%
Depreciation & Amortization	$8.800M	$8.400M	$7.900M
YoY Change	14.29%	9.09%	0.0%
% of Gross Profit	11.96%	11.59%	11.3%
Operating Expenses	$49.17M	$46.15M	$44.43M
YoY Change	2.52%	7.28%	-1.88%
Operating Profit	$24.41M	$26.30M	$25.51M
YoY Change	24.9%	16.65%	58.36%
Interest Expense	$940.0K	$1.000K	$0.00
YoY Change	-53.92%	-96.43%	-100.0%
% of Operating Profit	3.85%	0.0%	0.0%
Other Income/Expense, Net	$680.0K	$1.331M	$1.586M
YoY Change	-61.3%	-25.48%	-33.94%
Pretax Income	$25.09M	$27.63M	$27.09M
YoY Change	17.79%	13.56%	46.38%
Income Tax	$1.280M	$4.900M	$800.0K
% Of Pretax Income	5.1%	17.73%	2.95%
Net Earnings	$23.82M	$22.74M	$26.32M
YoY Change	15.25%	18.61%	62.14%
Net Earnings / Revenue	25.12%	24.44%	29.63%
Basic Earnings Per Share	$0.61	$0.58	$0.67
Diluted Earnings Per Share	$0.59	$0.56	$0.64
COMMON SHARES
Basic Shares Outstanding	39.02M	39.24M	39.16M
Diluted Shares Outstanding		40.76M	40.92M

Balance Sheet

Concept	2020 Q4	2020 Q3	2020 Q2
SHORT-TERM ASSETS
Cash & Short-Term Investments	$356.0M	$318.8M	$347.8M
YoY Change	19.12%	6.97%	16.32%
Cash & Equivalents	$74.13M	$93.03M	$113.9M
Short-Term Investments	$281.9M	$225.7M	$233.9M
Other Short-Term Assets	$19.10M	$22.50M	$24.30M
YoY Change	2.14%	9.76%	25.26%
Inventory
Prepaid Expenses
Receivables	$100.2M	$64.29M	$75.94M
Other Receivables	$0.00	$0.00	$0.00
Total Short-Term Assets	$475.3M	$405.5M	$448.1M
YoY Change	20.15%	6.77%	17.43%
LONG-TERM ASSETS
Property, Plant & Equipment	$64.85M	$67.57M	$63.10M
YoY Change	7.05%	15.11%	6.3%
Goodwill	$7.447M	$7.447M	$7.447M
YoY Change	0.0%	0.0%	1.67%
Intangibles	$12.01M	$13.65M	$13.76M
YoY Change	-28.51%	-25.47%	-30.66%
Long-Term Investments	$98.50M	$133.3M	$97.50M
YoY Change	-17.57%	31.98%	-12.56%
Other Assets	$16.86M	$16.85M	$16.02M
YoY Change	11.82%	19.1%	16.9%
Total Long-Term Assets	$261.5M	$301.6M	$258.9M
YoY Change	-6.61%	22.52%	-1.94%
TOTAL ASSETS
Total Short-Term Assets	$475.3M	$405.5M	$448.1M
Total Long-Term Assets	$261.5M	$301.6M	$258.9M
Total Assets	$736.8M	$707.1M	$707.0M
YoY Change	9.06%	12.97%	9.51%
SHORT-TERM LIABILITIES
YoY Change
Accounts Payable	$731.0K	$2.223M	$1.395M
YoY Change	-13.8%	144.55%	44.86%
Accrued Expenses	$29.83M	$24.77M	$24.81M
YoY Change	30.94%	-3.22%	2.04%
Deferred Revenue	$213.5M	$200.3M	$199.7M
YoY Change	11.1%	11.08%	13.09%
Short-Term Debt	$0.00	$0.00	$0.00
YoY Change
Long-Term Debt Due	$100.0K	$100.0K	$100.0K
YoY Change	0.0%	-80.0%	-85.71%
Total Short-Term Liabilities	$255.7M	$239.1M	$235.1M
YoY Change	14.44%	11.84%	12.64%
LONG-TERM LIABILITIES
Long-Term Debt	$0.00	$0.00	$0.00
YoY Change	-100.0%	-100.0%	-100.0%
Other Long-Term Liabilities	$367.0K	$181.0K	$23.00K
YoY Change	-5.41%	-40.46%	-95.2%
Total Long-Term Liabilities	$367.0K	$181.0K	$23.00K
YoY Change	-5.41%	-40.46%	-95.2%
TOTAL LIABILITIES
Total Short-Term Liabilities	$255.7M	$239.1M	$235.1M
Total Long-Term Liabilities	$367.0K	$181.0K	$23.00K
Total Liabilities	$332.3M	$306.8M	$299.2M
YoY Change	15.07%	15.81%	14.21%
SHAREHOLDERS EQUITY
Retained Earnings	$3.568M	$10.37M	$21.10M
YoY Change	-84.62%	-22.23%	-42.48%
Common Stock	$39.00K	$39.00K	$39.00K
YoY Change	0.0%	0.0%	0.0%
Preferred Stock
YoY Change
Treasury Stock (at cost)
YoY Change
Treasury Stock Shares
Shareholders Equity	$404.5M	$400.3M	$407.8M
YoY Change
Total Liabilities & Shareholders Equity	$736.8M	$707.1M	$707.0M
YoY Change	9.06%	12.97%	9.51%

Cashflow Statement

Concept	2020 Q4	2020 Q3	2020 Q2
OPERATING ACTIVITIES
Net Income	$23.82M	$22.74M	$26.32M
YoY Change	15.25%	18.61%	62.14%
Depreciation, Depletion And Amortization	$8.800M	$8.400M	$7.900M
YoY Change	14.29%	9.09%	0.0%
Cash From Operating Activities	$38.80M	$59.70M	$29.20M
YoY Change	15.13%	30.92%	-21.08%
INVESTING ACTIVITIES
Capital Expenditures	-$7.300M	-$11.10M	-$4.300M
YoY Change	-9.88%	105.56%	-21.82%
Acquisitions
YoY Change
Other Investing Activities	-$22.20M	-$29.90M	-$42.90M
YoY Change	131.25%	564.44%	146.55%
Cash From Investing Activities	-$29.40M	-$41.10M	-$47.20M
YoY Change	67.05%	315.15%	106.11%
FINANCING ACTIVITIES
Cash Dividend Paid
YoY Change
Common Stock Issuance & Retirement, Net
YoY Change
Debt Paid & Issued, Net
YoY Change
Cash From Financing Activities	-28.30M	-39.40M	-15.70M
YoY Change	607.5%	-23.64%	-0.63%
NET CHANGE
Cash From Operating Activities	38.80M	59.70M	29.20M
Cash From Investing Activities	-29.40M	-41.10M	-47.20M
Cash From Financing Activities	-28.30M	-39.40M	-15.70M
Net Change In Cash	-18.90M	-20.80M	-33.70M
YoY Change	-256.2%	30.82%	1882.35%
FREE CASH FLOW
Cash From Operating Activities	$38.80M	$59.70M	$29.20M
Capital Expenditures	-$7.300M	-$11.10M	-$4.300M
Free Cash Flow	$46.10M	$70.80M	$33.50M
YoY Change	10.29%	38.82%	-21.18%

Facts In Submission

Frame	Concept Type	Concept / XBRL Key	Value	Unit
CY2021Q1	dei	Entity Common Stock Shares Outstanding EntityCommonStockSharesOutstanding	39207735
CY2020Q4	us-gaap	Allowance For Doubtful Accounts Receivable AllowanceForDoubtfulAccountsReceivable	725000	USD
CY2019Q4	us-gaap	Allowance For Doubtful Accounts Receivable AllowanceForDoubtfulAccountsReceivable	585000	USD
CY2020Q4	us-gaap	Commitments And Contingencies CommitmentsAndContingencies		USD
CY2019Q4	us-gaap	Commitments And Contingencies CommitmentsAndContingencies		USD
CY2020Q4	us-gaap	Preferred Stock Par Or Stated Value Per Share PreferredStockParOrStatedValuePerShare	0.001
CY2019Q4	us-gaap	Preferred Stock Par Or Stated Value Per Share PreferredStockParOrStatedValuePerShare	0.001
CY2020Q4	us-gaap	Preferred Stock Shares Authorized PreferredStockSharesAuthorized	20000000
CY2019Q4	us-gaap	Preferred Stock Shares Authorized PreferredStockSharesAuthorized	20000000
CY2020Q4	us-gaap	Preferred Stock Shares Issued PreferredStockSharesIssued	0
CY2020	us-gaap	Cost Of Revenue CostOfRevenue	79226000	USD
CY2020Q4	us-gaap	Preferred Stock Shares Outstanding PreferredStockSharesOutstanding	0
CY2019Q4	us-gaap	Preferred Stock Shares Issued PreferredStockSharesIssued	0
CY2019Q4	us-gaap	Preferred Stock Shares Outstanding PreferredStockSharesOutstanding	0
CY2020Q4	us-gaap	Common Stock Par Or Stated Value Per Share CommonStockParOrStatedValuePerShare	0.001
CY2019Q4	us-gaap	Common Stock Par Or Stated Value Per Share CommonStockParOrStatedValuePerShare	0.001
CY2020Q4	us-gaap	Common Stock Shares Authorized CommonStockSharesAuthorized	1000000000
CY2019Q4	us-gaap	Common Stock Shares Authorized CommonStockSharesAuthorized	1000000000
CY2020Q4	us-gaap	Common Stock Shares Issued CommonStockSharesIssued	39252665
CY2020Q4	us-gaap	Common Stock Shares Outstanding CommonStockSharesOutstanding	39252665
CY2019Q4	us-gaap	Common Stock Shares Issued CommonStockSharesIssued	39146272
CY2019Q4	us-gaap	Common Stock Shares Outstanding CommonStockSharesOutstanding	39146272
CY2020	us-gaap	Other Comprehensive Income Loss Available For Sale Securities Before Reclassification Adjustments Tax OtherComprehensiveIncomeLossAvailableForSaleSecuritiesBeforeReclassificationAdjustmentsTax	128000	USD
CY2019	us-gaap	Other Comprehensive Income Loss Available For Sale Securities Before Reclassification Adjustments Tax OtherComprehensiveIncomeLossAvailableForSaleSecuritiesBeforeReclassificationAdjustmentsTax	243000	USD
CY2018	us-gaap	Other Comprehensive Income Loss Available For Sale Securities Before Reclassification Adjustments Tax OtherComprehensiveIncomeLossAvailableForSaleSecuritiesBeforeReclassificationAdjustmentsTax	-0	USD
CY2020	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci For Sale Of Securities Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesTax	6000	USD
CY2019	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci For Sale Of Securities Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesTax	0	USD
CY2018	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci For Sale Of Securities Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesTax	0	USD
CY2020	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss Before Reclassification Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossBeforeReclassificationTax	-486000	USD
CY2019	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss Before Reclassification Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossBeforeReclassificationTax	136000	USD
CY2018	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss Before Reclassification Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossBeforeReclassificationTax	-0	USD
CY2020	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss Reclassification Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossReclassificationTax	129000	USD
CY2019	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss Reclassification Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossReclassificationTax	35000	USD
CY2018	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss Reclassification Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossReclassificationTax	0	USD
CY2019Q4	us-gaap	Restricted Cash RestrictedCash	1200000	USD
CY2020	us-gaap	Proceeds From Dividends Received ProceedsFromDividendsReceived	0	USD
CY2019	us-gaap	Impairment Of Long Lived Assets Held For Use ImpairmentOfLongLivedAssetsHeldForUse	0	USD
CY2018	us-gaap	Impairment Of Long Lived Assets Held For Use ImpairmentOfLongLivedAssetsHeldForUse	0	USD
CY2019	us-gaap	Goodwill Impairment Loss GoodwillImpairmentLoss	0	USD
CY2019	us-gaap	Impairment Of Intangible Assets Excluding Goodwill ImpairmentOfIntangibleAssetsExcludingGoodwill	0	USD
CY2018	us-gaap	Impairment Of Intangible Assets Excluding Goodwill ImpairmentOfIntangibleAssetsExcludingGoodwill	0	USD
CY2020	qlys	Capitalized Contract Costt Amortization Period CapitalizedContractCosttAmortizationPeriod	P5Y
CY2019Q4	qlys	Marketable Securities In Unrealized Loss Positions More Than12 Months Qualitative Disclosure Number Of Positions MarketableSecuritiesInUnrealizedLossPositionsMoreThan12MonthsQualitativeDisclosureNumberOfPositions	0	pure
CY2020Q4	us-gaap	Revenue Remaining Performance Obligation Expected Timing Of Satisfaction Period1 RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionPeriod1	P1Y
CY2020Q4	us-gaap	Revenue Remaining Performance Obligation Expected Timing Of Satisfaction Period1 RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionPeriod1	P1Y
CY2020Q4	us-gaap	Revenue Remaining Performance Obligation Expected Timing Of Satisfaction Period1 RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionPeriod1	P1Y
CY2020Q4	us-gaap	Revenue Remaining Performance Obligation Expected Timing Of Satisfaction Period1 RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionPeriod1	P1Y
CY2020Q4	us-gaap	Revenue Remaining Performance Obligation Expected Timing Of Satisfaction Period1 RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionPeriod1	P1Y
CY2020Q4	us-gaap	Revenue Remaining Performance Obligation Expected Timing Of Satisfaction Period1 RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionPeriod1	P1Y
CY2019	us-gaap	Capitalized Contract Cost Impairment Loss CapitalizedContractCostImpairmentLoss	0	USD
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CY2020Q4	us-gaap	Lessee Operating Lease Renewal Term LesseeOperatingLeaseRenewalTerm	P4Y
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CY2020Q4	us-gaap	Preferred Stock Shares Outstanding PreferredStockSharesOutstanding	0
CY2019Q4	us-gaap	Preferred Stock Shares Outstanding PreferredStockSharesOutstanding	0
CY2018Q1	us-gaap	Stock Repurchase Program Period In Force1 StockRepurchaseProgramPeriodInForce1	P2Y
CY2019Q4	qlys	Stock Repurchase Program Additional Authorized Amount StockRepurchaseProgramAdditionalAuthorizedAmount	100000000.0	USD
CY2020Q2	qlys	Stock Repurchase Program Additional Authorized Amount StockRepurchaseProgramAdditionalAuthorizedAmount	100000000.0	USD
CY2020	us-gaap	Open Tax Year OpenTaxYear	2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019
CY2020Q4	us-gaap	Cash And Cash Equivalents At Carrying Value CashAndCashEquivalentsAtCarryingValue	74132000	USD
CY2019Q4	us-gaap	Cash And Cash Equivalents At Carrying Value CashAndCashEquivalentsAtCarryingValue	87559000	USD
CY2020Q4	us-gaap	Available For Sale Securities Debt Securities Current AvailableForSaleSecuritiesDebtSecuritiesCurrent	281892000	USD
CY2019Q4	us-gaap	Available For Sale Securities Debt Securities Current AvailableForSaleSecuritiesDebtSecuritiesCurrent	211331000	USD
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CY2020Q4	us-gaap	Available For Sale Securities Debt Securities Noncurrent AvailableForSaleSecuritiesDebtSecuritiesNoncurrent	98458000	USD
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CY2019Q4	us-gaap	Property Plant And Equipment Net PropertyPlantAndEquipmentNet	60579000	USD
CY2020Q4	us-gaap	Operating Lease Right Of Use Asset OperatingLeaseRightOfUseAsset	44838000	USD
CY2019Q4	us-gaap	Operating Lease Right Of Use Asset OperatingLeaseRightOfUseAsset	40551000	USD
CY2020Q4	us-gaap	Deferred Income Tax Assets Net DeferredIncomeTaxAssetsNet	15811000	USD
CY2019Q4	us-gaap	Deferred Income Tax Assets Net DeferredIncomeTaxAssetsNet	18830000	USD
CY2020Q4	us-gaap	Intangible Assets Net Excluding Goodwill IntangibleAssetsNetExcludingGoodwill	12006000	USD
CY2019Q4	us-gaap	Intangible Assets Net Excluding Goodwill IntangibleAssetsNetExcludingGoodwill	16795000	USD
CY2020Q4	us-gaap	Goodwill Goodwill	7447000	USD
CY2019Q4	us-gaap	Goodwill Goodwill	7447000	USD
CY2020Q4	us-gaap	Restricted Cash And Cash Equivalents Noncurrent RestrictedCashAndCashEquivalentsNoncurrent	1200000	USD
CY2019Q4	us-gaap	Restricted Cash And Cash Equivalents Noncurrent RestrictedCashAndCashEquivalentsNoncurrent	1200000	USD
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CY2020Q4	us-gaap	Assets Assets	736819000	USD
CY2019Q4	us-gaap	Assets Assets	675608000	USD
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CY2019Q4	us-gaap	Accounts Payable Current AccountsPayableCurrent	848000	USD
CY2020Q4	us-gaap	Accrued Liabilities Current AccruedLiabilitiesCurrent	29833000	USD
CY2019Q4	us-gaap	Accrued Liabilities Current AccruedLiabilitiesCurrent	22784000	USD
CY2020Q4	us-gaap	Contract With Customer Liability Current ContractWithCustomerLiabilityCurrent	213494000	USD
CY2019Q4	us-gaap	Contract With Customer Liability Current ContractWithCustomerLiabilityCurrent	192172000	USD
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CY2020Q4	us-gaap	Other Liabilities Noncurrent OtherLiabilitiesNoncurrent	367000	USD
CY2019Q4	us-gaap	Other Liabilities Noncurrent OtherLiabilitiesNoncurrent	388000	USD
CY2020Q4	us-gaap	Liabilities Liabilities	332337000	USD
CY2019Q4	us-gaap	Liabilities Liabilities	288805000	USD
CY2020Q4	us-gaap	Preferred Stock Value PreferredStockValue	0	USD
CY2019Q4	us-gaap	Preferred Stock Value PreferredStockValue	0	USD
CY2020Q4	us-gaap	Common Stock Value CommonStockValue	39000	USD
CY2019Q4	us-gaap	Common Stock Value CommonStockValue	39000	USD
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CY2019Q4	us-gaap	Additional Paid In Capital AdditionalPaidInCapital	362408000	USD
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CY2020Q4	us-gaap	Stockholders Equity StockholdersEquity	404482000	USD
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CY2020	us-gaap	Revenue From Contract With Customer Excluding Assessed Tax RevenueFromContractWithCustomerExcludingAssessedTax	362963000	USD
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CY2019	us-gaap	Operating Expenses OperatingExpenses	179837000	USD
CY2018	us-gaap	Nonoperating Income Expense NonoperatingIncomeExpense	5107000	USD
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CY2020	us-gaap	Operating Income Loss OperatingIncomeLoss	96654000	USD
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CY2019	us-gaap	Interest Expense InterestExpense	106000	USD
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CY2020	us-gaap	Investment Income Interest InvestmentIncomeInterest	5385000	USD
CY2019	us-gaap	Investment Income Interest InvestmentIncomeInterest	8443000	USD
CY2018	us-gaap	Investment Income Interest InvestmentIncomeInterest	6080000	USD
CY2020	us-gaap	Other Nonoperating Income Expense OtherNonoperatingIncomeExpense	7000	USD
CY2019	us-gaap	Other Nonoperating Income Expense OtherNonoperatingIncomeExpense	-607000	USD
CY2018	us-gaap	Other Nonoperating Income Expense OtherNonoperatingIncomeExpense	-801000	USD
CY2020	us-gaap	Nonoperating Income Expense NonoperatingIncomeExpense	5383000	USD
CY2019	us-gaap	Nonoperating Income Expense NonoperatingIncomeExpense	7730000	USD
CY2018	us-gaap	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments	55468000	USD
CY2020	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	10465000	USD
CY2019	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	10647000	USD
CY2018	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	-1836000	USD
CY2020	us-gaap	Net Income Loss NetIncomeLoss	91572000	USD
CY2019	us-gaap	Net Income Loss NetIncomeLoss	69336000	USD
CY2018	us-gaap	Net Income Loss NetIncomeLoss	57304000	USD
CY2020	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	2.34
CY2019	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	1.77
CY2018	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	1.47
CY2020	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	2.24
CY2019	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	1.68
CY2018	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	1.37
CY2020	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	39167000
CY2019	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	39075000
CY2018	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	38876000
CY2020	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	40823000
CY2019	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	41345000
CY2018	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	41897000
CY2020	us-gaap	Net Income Loss NetIncomeLoss	91572000	USD
CY2019	us-gaap	Net Income Loss NetIncomeLoss	69336000	USD
CY2018	us-gaap	Net Income Loss NetIncomeLoss	57304000	USD
CY2019	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent	1748000	USD
CY2018	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent	-12000	USD
CY2019	us-gaap	Gain Loss On Sale Of Property Plant Equipment GainLossOnSaleOfPropertyPlantEquipment	-202000	USD
CY2018	us-gaap	Gain Loss On Sale Of Property Plant Equipment GainLossOnSaleOfPropertyPlantEquipment	-9000	USD
CY2020	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Net Of Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax	421000	USD
CY2019	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Net Of Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax	1367000	USD
CY2018	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Net Of Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax	-261000	USD
CY2020	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci For Sale Of Securities Net Of Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesNetOfTax	19000	USD
CY2019	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci For Sale Of Securities Net Of Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesNetOfTax	-0	USD
CY2018	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci For Sale Of Securities Net Of Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesNetOfTax	-289000	USD
CY2020	us-gaap	Other Comprehensive Income Loss Available For Sale Securities Adjustment Net Of Tax OtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentNetOfTax	402000	USD
CY2019	us-gaap	Other Comprehensive Income Loss Available For Sale Securities Adjustment Net Of Tax OtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentNetOfTax	1367000	USD
CY2018	us-gaap	Other Comprehensive Income Loss Available For Sale Securities Adjustment Net Of Tax OtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentNetOfTax	28000	USD
CY2020	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss Before Reclassification After Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossBeforeReclassificationAfterTax	-1613000	USD
CY2019	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss Before Reclassification After Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossBeforeReclassificationAfterTax	515000	USD
CY2018	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss Before Reclassification After Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossBeforeReclassificationAfterTax	-40000	USD
CY2020	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss Reclassification After Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossReclassificationAfterTax	435000	USD
CY2019	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss Reclassification After Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossReclassificationAfterTax	134000	USD
CY2018	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss Reclassification After Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossReclassificationAfterTax	-0	USD
CY2020	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss After Reclassification And Tax Parent OtherComprehensiveIncomeLossCashFlowHedgeGainLossAfterReclassificationAndTaxParent	-2048000	USD
CY2019	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss After Reclassification And Tax Parent OtherComprehensiveIncomeLossCashFlowHedgeGainLossAfterReclassificationAndTaxParent	381000	USD
CY2018	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss After Reclassification And Tax Parent OtherComprehensiveIncomeLossCashFlowHedgeGainLossAfterReclassificationAndTaxParent	-40000	USD
CY2020	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent	-1646000	USD
CY2020	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	89926000	USD
CY2019	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	71084000	USD
CY2018	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	57292000	USD
CY2020	us-gaap	Net Income Loss NetIncomeLoss	91572000	USD
CY2019	us-gaap	Net Income Loss NetIncomeLoss	69336000	USD
CY2018	us-gaap	Net Income Loss NetIncomeLoss	57304000	USD
CY2020	us-gaap	Depreciation Depletion And Amortization DepreciationDepletionAndAmortization	32845000	USD
CY2019	us-gaap	Depreciation Depletion And Amortization DepreciationDepletionAndAmortization	31201000	USD
CY2018	us-gaap	Depreciation Depletion And Amortization DepreciationDepletionAndAmortization	28904000	USD
CY2020	us-gaap	Provision For Doubtful Accounts ProvisionForDoubtfulAccounts	486000	USD
CY2019	us-gaap	Provision For Doubtful Accounts ProvisionForDoubtfulAccounts	247000	USD
CY2018	us-gaap	Provision For Doubtful Accounts ProvisionForDoubtfulAccounts	86000	USD
CY2020	us-gaap	Gain Loss On Sale Of Property Plant Equipment GainLossOnSaleOfPropertyPlantEquipment	-106000	USD
CY2020	us-gaap	Share Based Compensation ShareBasedCompensation	40035000	USD
CY2019	us-gaap	Share Based Compensation ShareBasedCompensation	34892000	USD
CY2018	us-gaap	Share Based Compensation ShareBasedCompensation	30090000	USD
CY2020	us-gaap	Accretion Amortization Of Discounts And Premiums Investments AccretionAmortizationOfDiscountsAndPremiumsInvestments	-826000	USD
CY2019	us-gaap	Accretion Amortization Of Discounts And Premiums Investments AccretionAmortizationOfDiscountsAndPremiumsInvestments	1597000	USD
CY2018	us-gaap	Accretion Amortization Of Discounts And Premiums Investments AccretionAmortizationOfDiscountsAndPremiumsInvestments	1136000	USD
CY2020	us-gaap	Deferred Income Taxes And Tax Credits DeferredIncomeTaxesAndTaxCredits	3512000	USD
CY2019	us-gaap	Deferred Income Taxes And Tax Credits DeferredIncomeTaxesAndTaxCredits	7095000	USD
CY2018	us-gaap	Deferred Income Taxes And Tax Credits DeferredIncomeTaxesAndTaxCredits	-2521000	USD
CY2020	us-gaap	Increase Decrease In Accounts Receivable IncreaseDecreaseInAccountsReceivable	22631000	USD
CY2019	us-gaap	Increase Decrease In Accounts Receivable IncreaseDecreaseInAccountsReceivable	2456000	USD
CY2018	us-gaap	Increase Decrease In Accounts Receivable IncreaseDecreaseInAccountsReceivable	11467000	USD
CY2020	us-gaap	Increase Decrease In Prepaid Deferred Expense And Other Assets IncreaseDecreaseInPrepaidDeferredExpenseAndOtherAssets	2329000	USD
CY2019	us-gaap	Increase Decrease In Prepaid Deferred Expense And Other Assets IncreaseDecreaseInPrepaidDeferredExpenseAndOtherAssets	6012000	USD
CY2018	us-gaap	Increase Decrease In Prepaid Deferred Expense And Other Assets IncreaseDecreaseInPrepaidDeferredExpenseAndOtherAssets	4970000	USD
CY2020	us-gaap	Increase Decrease In Accounts Payable IncreaseDecreaseInAccountsPayable	-389000	USD
CY2019	us-gaap	Increase Decrease In Accounts Payable IncreaseDecreaseInAccountsPayable	-1076000	USD
CY2018	us-gaap	Increase Decrease In Accounts Payable IncreaseDecreaseInAccountsPayable	3515000	USD
CY2020	us-gaap	Proceeds From Sale And Maturity Of Marketable Securities ProceedsFromSaleAndMaturityOfMarketableSecurities	341879000	USD
CY2019	us-gaap	Proceeds From Sale And Maturity Of Marketable Securities ProceedsFromSaleAndMaturityOfMarketableSecurities	328350000	USD
CY2018	us-gaap	Proceeds From Sale And Maturity Of Marketable Securities ProceedsFromSaleAndMaturityOfMarketableSecurities	285224000	USD
CY2020	us-gaap	Payments To Acquire Property Plant And Equipment PaymentsToAcquirePropertyPlantAndEquipment	30037000	USD
CY2019	us-gaap	Payments For Repurchase Of Common Stock PaymentsForRepurchaseOfCommonStock	86424000	USD
CY2018	us-gaap	Payments For Repurchase Of Common Stock PaymentsForRepurchaseOfCommonStock	85040000	USD
CY2017Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Including Disposal Group And Discontinued Operations CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsIncludingDisposalGroupAndDiscontinuedOperations	87791000	USD
CY2020Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Including Disposal Group And Discontinued Operations CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsIncludingDisposalGroupAndDiscontinuedOperations	75332000	USD
CY2018	qlys	Payments To Acquire Privatelyheld Investments PaymentsToAcquirePrivatelyheldInvestments	2500000	USD
CY2020	us-gaap	Net Cash Provided By Used In Investing Activities NetCashProvidedByUsedInInvestingActivities	-80932000	USD
CY2019	us-gaap	Payments To Acquire Property Plant And Equipment PaymentsToAcquirePropertyPlantAndEquipment	27573000	USD
CY2019	us-gaap	Net Cash Provided By Used In Investing Activities NetCashProvidedByUsedInInvestingActivities	-35029000	USD
CY2019	us-gaap	Payments To Acquire Marketable Securities PaymentsToAcquireMarketableSecurities	331131000	USD
CY2018	us-gaap	Payments To Acquire Marketable Securities PaymentsToAcquireMarketableSecurities	339862000	USD
CY2018	us-gaap	Net Cash Provided By Used In Investing Activities NetCashProvidedByUsedInInvestingActivities	-93546000	USD
CY2020	us-gaap	Payments For Repurchase Of Common Stock PaymentsForRepurchaseOfCommonStock	126729000	USD
CY2020	us-gaap	Increase Decrease In Accrued Liabilities IncreaseDecreaseInAccruedLiabilities	5126000	USD
CY2019	us-gaap	Increase Decrease In Accrued Liabilities IncreaseDecreaseInAccruedLiabilities	715000	USD
CY2018	us-gaap	Increase Decrease In Accrued Liabilities IncreaseDecreaseInAccruedLiabilities	1426000	USD
CY2020	us-gaap	Increase Decrease In Contract With Customer Liability IncreaseDecreaseInContractWithCustomerLiability	30927000	USD
CY2019	us-gaap	Increase Decrease In Contract With Customer Liability IncreaseDecreaseInContractWithCustomerLiability	28060000	USD
CY2018	us-gaap	Increase Decrease In Contract With Customer Liability IncreaseDecreaseInContractWithCustomerLiability	24725000	USD
CY2020	us-gaap	Increase Decrease In Other Noncurrent Liabilities IncreaseDecreaseInOtherNoncurrentLiabilities	0	USD
CY2019	us-gaap	Increase Decrease In Other Noncurrent Liabilities IncreaseDecreaseInOtherNoncurrentLiabilities	0	USD
CY2018	us-gaap	Increase Decrease In Other Noncurrent Liabilities IncreaseDecreaseInOtherNoncurrentLiabilities	-501000	USD
CY2020	us-gaap	Net Cash Provided By Used In Operating Activities NetCashProvidedByUsedInOperatingActivities	180086000	USD
CY2019	us-gaap	Net Cash Provided By Used In Operating Activities NetCashProvidedByUsedInOperatingActivities	160607000	USD
CY2018	us-gaap	Net Cash Provided By Used In Operating Activities NetCashProvidedByUsedInOperatingActivities	125464000	USD
CY2020	us-gaap	Payments To Acquire Marketable Securities PaymentsToAcquireMarketableSecurities	391693000	USD
CY2018	us-gaap	Payments To Acquire Property Plant And Equipment PaymentsToAcquirePropertyPlantAndEquipment	22775000	USD
CY2020	us-gaap	Proceeds From Sale Of Property Plant And Equipment ProceedsFromSaleOfPropertyPlantAndEquipment	419000	USD
CY2019	us-gaap	Proceeds From Sale Of Property Plant And Equipment ProceedsFromSaleOfPropertyPlantAndEquipment	0	USD
CY2018	us-gaap	Proceeds From Sale Of Property Plant And Equipment ProceedsFromSaleOfPropertyPlantAndEquipment	0	USD
CY2020	us-gaap	Payments To Acquire Businesses Gross PaymentsToAcquireBusinessesGross	1500000	USD
CY2019	us-gaap	Payments To Acquire Businesses Gross PaymentsToAcquireBusinessesGross	4050000	USD
CY2018	us-gaap	Payments To Acquire Businesses Gross PaymentsToAcquireBusinessesGross	13633000	USD
CY2020	qlys	Payments To Acquire Privatelyheld Investments PaymentsToAcquirePrivatelyheldInvestments	-0	USD
CY2019	qlys	Payments To Acquire Privatelyheld Investments PaymentsToAcquirePrivatelyheldInvestments	625000	USD
CY2020	us-gaap	Proceeds From Stock Options Exercised ProceedsFromStockOptionsExercised	34461000	USD
CY2019	us-gaap	Proceeds From Stock Options Exercised ProceedsFromStockOptionsExercised	24831000	USD
CY2018	us-gaap	Proceeds From Stock Options Exercised ProceedsFromStockOptionsExercised	24053000	USD
CY2020	us-gaap	Payments Related To Tax Withholding For Share Based Compensation PaymentsRelatedToTaxWithholdingForShareBasedCompensation	20199000	USD
CY2019	us-gaap	Payments Related To Tax Withholding For Share Based Compensation PaymentsRelatedToTaxWithholdingForShareBasedCompensation	15743000	USD
CY2018	us-gaap	Payments Related To Tax Withholding For Share Based Compensation PaymentsRelatedToTaxWithholdingForShareBasedCompensation	14879000	USD
CY2020	us-gaap	Repayments Of Long Term Capital Lease Obligations RepaymentsOfLongTermCapitalLeaseObligations	114000	USD
CY2019	us-gaap	Repayments Of Long Term Capital Lease Obligations RepaymentsOfLongTermCapitalLeaseObligations	1709000	USD
CY2018	us-gaap	Repayments Of Long Term Capital Lease Obligations RepaymentsOfLongTermCapitalLeaseObligations	1617000	USD
CY2020	us-gaap	Net Cash Provided By Used In Financing Activities NetCashProvidedByUsedInFinancingActivities	-112581000	USD
CY2019	us-gaap	Net Cash Provided By Used In Financing Activities NetCashProvidedByUsedInFinancingActivities	-79045000	USD
CY2018	us-gaap	Net Cash Provided By Used In Financing Activities NetCashProvidedByUsedInFinancingActivities	-77483000	USD
CY2020	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Period Increase Decrease Including Exchange Rate Effect CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect	-13427000	USD
CY2019	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Period Increase Decrease Including Exchange Rate Effect CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect	46533000	USD
CY2018	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Period Increase Decrease Including Exchange Rate Effect CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect	-45565000	USD
CY2019Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Including Disposal Group And Discontinued Operations CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsIncludingDisposalGroupAndDiscontinuedOperations	88759000	USD
CY2018Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Including Disposal Group And Discontinued Operations CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsIncludingDisposalGroupAndDiscontinuedOperations	42226000	USD
CY2018	us-gaap	Stock Repurchased During Period Value StockRepurchasedDuringPeriodValue	85040000	USD
CY2018	qlys	Stock Issued During Period Value Restricted Stock Award Vested StockIssuedDuringPeriodValueRestrictedStockAwardVested	0	USD
CY2020	us-gaap	Net Income Loss NetIncomeLoss	91572000	USD
CY2018	us-gaap	Adjustments Related To Tax Withholding For Share Based Compensation AdjustmentsRelatedToTaxWithholdingForShareBasedCompensation	14879000	USD
CY2020	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent	-1646000	USD
CY2020	us-gaap	Stock Issued During Period Value Stock Options Exercised StockIssuedDuringPeriodValueStockOptionsExercised	34461000	USD
CY2020	us-gaap	Stock Repurchased During Period Value StockRepurchasedDuringPeriodValue	126729000	USD
CY2020	qlys	Stock Issued During Period Value Restricted Stock Award Vested StockIssuedDuringPeriodValueRestrictedStockAwardVested	0	USD
CY2019Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Including Disposal Group And Discontinued Operations CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsIncludingDisposalGroupAndDiscontinuedOperations	88759000	USD
CY2018Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Including Disposal Group And Discontinued Operations CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsIncludingDisposalGroupAndDiscontinuedOperations	42226000	USD
CY2020	us-gaap	Interest Paid Net InterestPaidNet	9000	USD
CY2019	us-gaap	Interest Paid Net InterestPaidNet	107000	USD
CY2018	us-gaap	Interest Paid Net InterestPaidNet	168000	USD
CY2020	us-gaap	Income Taxes Paid Net IncomeTaxesPaidNet	8058000	USD
CY2019	us-gaap	Income Taxes Paid Net IncomeTaxesPaidNet	3031000	USD
CY2018	us-gaap	Income Taxes Paid Net IncomeTaxesPaidNet	2693000	USD
CY2020	us-gaap	Noncash Or Part Noncash Acquisition Net Nonmonetary Assets Acquired Liabilities Assumed1 NoncashOrPartNoncashAcquisitionNetNonmonetaryAssetsAcquiredLiabilitiesAssumed1	150000	USD
CY2019	us-gaap	Noncash Or Part Noncash Acquisition Net Nonmonetary Assets Acquired Liabilities Assumed1 NoncashOrPartNoncashAcquisitionNetNonmonetaryAssetsAcquiredLiabilitiesAssumed1	150000	USD
CY2018	us-gaap	Noncash Or Part Noncash Acquisition Net Nonmonetary Assets Acquired Liabilities Assumed1 NoncashOrPartNoncashAcquisitionNetNonmonetaryAssetsAcquiredLiabilitiesAssumed1	4676000	USD
CY2020	us-gaap	Capital Expenditures Incurred But Not Yet Paid CapitalExpendituresIncurredButNotYetPaid	1054000	USD
CY2019	us-gaap	Capital Expenditures Incurred But Not Yet Paid CapitalExpendituresIncurredButNotYetPaid	235000	USD
CY2018	us-gaap	Capital Expenditures Incurred But Not Yet Paid CapitalExpendituresIncurredButNotYetPaid	4190000	USD
CY2017Q4	us-gaap	Stockholders Equity StockholdersEquity	343544000	USD
CY2018	us-gaap	Net Income Loss NetIncomeLoss	57304000	USD
CY2018	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent	-12000	USD
CY2018	us-gaap	Stock Issued During Period Value Stock Options Exercised StockIssuedDuringPeriodValueStockOptionsExercised	24053000	USD
CY2018	us-gaap	Adjustments To Additional Paid In Capital Sharebased Compensation Requisite Service Period Recognition Value AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue	30308000	USD
CY2018Q4	us-gaap	Stockholders Equity StockholdersEquity	357989000	USD
CY2019	us-gaap	Net Income Loss NetIncomeLoss	69336000	USD
CY2019	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent	1748000	USD
CY2019	us-gaap	Stock Issued During Period Value Stock Options Exercised StockIssuedDuringPeriodValueStockOptionsExercised	24831000	USD
CY2019	us-gaap	Stock Repurchased During Period Value StockRepurchasedDuringPeriodValue	86424000	USD
CY2019	qlys	Stock Issued During Period Value Restricted Stock Award Vested StockIssuedDuringPeriodValueRestrictedStockAwardVested	0	USD
CY2019	us-gaap	Adjustments Related To Tax Withholding For Share Based Compensation AdjustmentsRelatedToTaxWithholdingForShareBasedCompensation	15743000	USD
CY2019	us-gaap	Adjustments To Additional Paid In Capital Sharebased Compensation Requisite Service Period Recognition Value AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue	35066000	USD
CY2019Q4	us-gaap	Stockholders Equity StockholdersEquity	386803000	USD
CY2020	us-gaap	Adjustments Related To Tax Withholding For Share Based Compensation AdjustmentsRelatedToTaxWithholdingForShareBasedCompensation	20199000	USD
CY2020	us-gaap	Adjustments To Additional Paid In Capital Sharebased Compensation Requisite Service Period Recognition Value AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue	40220000	USD
CY2020Q4	us-gaap	Stockholders Equity StockholdersEquity	404482000	USD
CY2020	us-gaap	Use Of Estimates UseOfEstimates	<p style="font-family:'Times New Roman', Times, serif;font-size:10pt;margin:0pt;text-align:justify;text-indent:9pt;"><i><b>Use of Estimates</b></i></p> <p style="font-family:'Times New Roman', Times, serif;font-size:10pt;margin:0pt;text-align:justify;text-indent:22.5pt;"> </p> <p style="font-family:'Times New Roman', Times, serif;font-size:10pt;margin:0pt;text-align:justify;text-indent:22.5pt;">The preparation of the consolidated financial statements in conformity with U.S. GAAP requires management to make certain estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of assets and liabilities at the date of the consolidated financial statements and the reported results of operations during the reporting period. The Company’s management regularly assesses these estimates, which primarily affect revenue recognition, the valuation of accounts receivable, goodwill and intangible assets, capitalization of internally developed software, stock-based compensation and the provision for income taxes. Actual results could differ from those estimates and such differences <em style="font: inherit;"> may </em>be material to the accompanying consolidated financial statements.</p> <p style="font-family:'Times New Roman', Times, serif;font-size:10pt;margin:0pt;text-align:justify;text-indent:22.5pt;"> </p>
CY2020	us-gaap	Impairment Of Long Lived Assets Held For Use ImpairmentOfLongLivedAssetsHeldForUse	0	USD
CY2020Q4	us-gaap	Cash And Cash Equivalents Fair Value Disclosure CashAndCashEquivalentsFairValueDisclosure	74132000	USD
CY2020	us-gaap	Concentration Risk Credit Risk ConcentrationRiskCreditRisk	<p style="font-family:'Times New Roman', Times, serif;font-size:10pt;margin:0pt;text-align:justify;text-indent:13.5pt;"><i><b>Concentration of Credit Risk</b></i></p> <p style="font-family:'Times New Roman', Times, serif;font-size:10pt;margin:0pt;text-align:justify;text-indent:22.5pt;"> </p> <p style="font-family:'Times New Roman', Times, serif;font-size:10pt;margin:0pt;text-align:justify;text-indent:22.5pt;">The Company invests its cash and cash equivalents with major financial institutions. Cash balances with any <em style="font: inherit;">one</em> institution at times <em style="font: inherit;"> may </em>be in excess of federally insured limits. Cash equivalents are invested in high-quality investment grade financial instruments and are diversified. The Company has <em style="font: inherit;">not</em> experienced any losses in such accounts and believes it is <em style="font: inherit;">not</em> exposed to any significant credit risk.</p> <p style="font-family:'Times New Roman', Times, serif;font-size:10pt;margin:0pt;text-align:justify;text-indent:22.5pt;"> </p> <p style="font-family:'Times New Roman', Times, serif;font-size:10pt;margin:0pt;text-align:justify;text-indent:22.5pt;">Credit risk with respect to accounts receivable is dispersed due to the large number of customers. Collateral is <em style="font: inherit;">not</em> required for accounts receivable. As of <em style="font: inherit;"> December 31, 2020</em> and <em style="font: inherit;">2019</em>, <em style="font: inherit;">no</em> customer or channel partner accounted for more than <em style="font: inherit;">10%</em> of the Company's revenues and accounts receivable balance.</p> <p style="font-family:'Times New Roman', Times, serif;font-size:10pt;margin:0pt;text-align:justify;text-indent:22.5pt;"> </p>
CY2020Q4	us-gaap	Restricted Cash RestrictedCash	1200000	USD
CY2020	us-gaap	Number Of Reporting Units NumberOfReportingUnits	1	pure
CY2020	us-gaap	Goodwill Impairment Loss GoodwillImpairmentLoss	0	USD
CY2020	us-gaap	Impairment Of Intangible Assets Excluding Goodwill ImpairmentOfIntangibleAssetsExcludingGoodwill	0	USD
CY2020Q4	us-gaap	Capitalized Computer Software Gross CapitalizedComputerSoftwareGross	1000000.0	USD
CY2019Q4	us-gaap	Capitalized Computer Software Gross CapitalizedComputerSoftwareGross	1000000.0	USD
CY2018Q4	us-gaap	Capitalized Computer Software Gross CapitalizedComputerSoftwareGross	1300000	USD
CY2020Q4	qlys	Capitalized Computer Software Unamortized CapitalizedComputerSoftwareUnamortized	2600000	USD
CY2019Q4	qlys	Capitalized Computer Software Unamortized CapitalizedComputerSoftwareUnamortized	2000000.0	USD
CY2020Q4	us-gaap	Cash And Cash Equivalents Fair Value Disclosure CashAndCashEquivalentsFairValueDisclosure	74132000	USD
CY2020	us-gaap	Derivatives Reporting Of Derivative Activity DerivativesReportingOfDerivativeActivity	<p style="font-family: "Times New Roman", Times, serif; font-size: 10pt; margin: 0pt; text-align: justify; text-indent: 13.5pt;"><i><b>Derivative Financial Instruments</b></i></p> <p style="font-family:'Times New Roman', Times, serif;font-size:10pt;margin:0pt;text-align:justify;text-indent:22.5pt;"> </p> <p style="font-family:'Times New Roman', Times, serif;font-size:10pt;margin:0pt;text-align:justify;text-indent:22.5pt;">Derivative financial instruments are utilized by the Company to reduce foreign currency exchange risks. The Company uses foreign currency forward contracts, with maturities of <em style="font: inherit;">13</em> months or less, to mitigate the impact of foreign currency fluctuations of certain non-U.S. dollar denominated net asset positions, to date primarily cash, accounts receivable and operating lease liabilities, as well as to manage foreign currency fluctuation risk related to forecasted transactions. Open contracts are recorded within prepaid expenses and other current assets, other noncurrent assets, accrued liabilities or other noncurrent liabilities in the consolidated balance sheets. Gains and losses resulting from currency exchange rate movements on non-designated forward contracts are recognized in other income (expense), net. Any gains or losses from derivatives designated as cash flow hedges are <em style="font: inherit;">first</em> recorded within accumulated other comprehensive income ("AOCI") and then reclassified into revenue or operating expenses when the hedged item impacts the consolidated statements of operations. Cash flows related to these forward contracts are classified in our consolidated statements of cash flows in the same manner as the underlying hedged transaction within cash flows from operating activities.</p> <p style="font-family:'Times New Roman', Times, serif;font-size:10pt;margin:0pt;text-align:justify;text-indent:9pt;"> </p>
CY2020	us-gaap	Advertising Expense AdvertisingExpense	207000	USD
CY2019	us-gaap	Advertising Expense AdvertisingExpense	74000	USD
CY2018	us-gaap	Advertising Expense AdvertisingExpense	87000	USD
CY2020	us-gaap	Foreign Currency Transaction Gain Loss Before Tax ForeignCurrencyTransactionGainLossBeforeTax	260000	USD
CY2020	us-gaap	Foreign Currency Transaction Gain Before Tax ForeignCurrencyTransactionGainBeforeTax	300000	USD
CY2019	us-gaap	Foreign Currency Transaction Loss Before Tax ForeignCurrencyTransactionLossBeforeTax	400000	USD
CY2018	us-gaap	Foreign Currency Transaction Loss Before Tax ForeignCurrencyTransactionLossBeforeTax	600000	USD
CY2020Q4	qlys	Available For Sale Debt Securities Amortized Cost Basis Current AvailableForSaleDebtSecuritiesAmortizedCostBasisCurrent	281346000	USD
CY2020Q4	qlys	Available For Sale Debt Securities Accumulated Gross Unrealized Gain Before Tax Current AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTaxCurrent	557000	USD
CY2020Q4	qlys	Availableforsale Debt Securities Accumulated Gross Unrealized Loss Before Tax Current AvailableforsaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTaxCurrent	11000	USD
CY2020Q4	us-gaap	Available For Sale Securities Debt Securities Current AvailableForSaleSecuritiesDebtSecuritiesCurrent	281892000	USD
CY2020Q4	qlys	Available For Sale Debt Securities Amortized Cost Basis Noncurrent AvailableForSaleDebtSecuritiesAmortizedCostBasisNoncurrent	97414000	USD
CY2020Q4	qlys	Available For Sale Debt Securities Accumulated Gross Unrealized Gain Before Tax Noncurrent AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTaxNoncurrent	1047000	USD
CY2020Q4	qlys	Available For Sale Debt Securities Accumulated Gross Unrealized Loss Before Tax Noncurrent AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTaxNoncurrent	3000	USD
CY2020Q4	us-gaap	Available For Sale Securities Debt Securities Noncurrent AvailableForSaleSecuritiesDebtSecuritiesNoncurrent	98458000	USD
CY2020Q4	qlys	Cash And Cash Equivalent And Debt Securities Availableforsale Amortized Cost Total CashAndCashEquivalentAndDebtSecuritiesAvailableforsaleAmortizedCostTotal	452892000	USD
CY2020Q4	us-gaap	Available For Sale Debt Securities Accumulated Gross Unrealized Gain Before Tax AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax	1604000	USD
CY2020Q4	us-gaap	Available For Sale Debt Securities Accumulated Gross Unrealized Loss Before Tax AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax	14000	USD
CY2020Q4	qlys	Cash And Cash Equivalent And St And Lt Debt Securities Availableforsale Fair Value Disclosure CashAndCashEquivalentAndStAndLtDebtSecuritiesAvailableforsaleFairValueDisclosure	454482000	USD
CY2019Q4	us-gaap	Cash And Cash Equivalents Fair Value Disclosure CashAndCashEquivalentsFairValueDisclosure	87559000	USD
CY2019Q4	us-gaap	Cash And Cash Equivalents Fair Value Disclosure CashAndCashEquivalentsFairValueDisclosure	87559000	USD
CY2019Q4	qlys	Available For Sale Debt Securities Amortized Cost Basis Current AvailableForSaleDebtSecuritiesAmortizedCostBasisCurrent	211089000	USD
CY2019Q4	qlys	Available For Sale Debt Securities Accumulated Gross Unrealized Gain Before Tax Current AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTaxCurrent	246000	USD
CY2019Q4	qlys	Availableforsale Debt Securities Accumulated Gross Unrealized Loss Before Tax Current AvailableforsaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTaxCurrent	4000	USD
CY2019Q4	us-gaap	Available For Sale Securities Debt Securities Current AvailableForSaleSecuritiesDebtSecuritiesCurrent	211331000	USD
CY2019Q4	qlys	Available For Sale Debt Securities Amortized Cost Basis Noncurrent AvailableForSaleDebtSecuritiesAmortizedCostBasisNoncurrent	118684000	USD
CY2019Q4	qlys	Available For Sale Debt Securities Accumulated Gross Unrealized Gain Before Tax Noncurrent AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTaxNoncurrent	825000	USD
CY2019Q4	qlys	Available For Sale Debt Securities Accumulated Gross Unrealized Loss Before Tax Noncurrent AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTaxNoncurrent	1000	USD
CY2019Q4	us-gaap	Available For Sale Securities Debt Securities Noncurrent AvailableForSaleSecuritiesDebtSecuritiesNoncurrent	119508000	USD
CY2019Q4	qlys	Cash And Cash Equivalent And Debt Securities Availableforsale Amortized Cost Total CashAndCashEquivalentAndDebtSecuritiesAvailableforsaleAmortizedCostTotal	417332000	USD
CY2019Q4	us-gaap	Available For Sale Debt Securities Accumulated Gross Unrealized Gain Before Tax AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax	1071000	USD
CY2019Q4	us-gaap	Available For Sale Debt Securities Accumulated Gross Unrealized Loss Before Tax AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax	5000	USD
CY2019Q4	qlys	Cash And Cash Equivalent And St And Lt Debt Securities Availableforsale Fair Value Disclosure CashAndCashEquivalentAndStAndLtDebtSecuritiesAvailableforsaleFairValueDisclosure	418398000	USD
CY2020Q4	qlys	Marketable Securities In Unrealized Loss Positions More Than12 Months Qualitative Disclosure Number Of Positions MarketableSecuritiesInUnrealizedLossPositionsMoreThan12MonthsQualitativeDisclosureNumberOfPositions	0	pure
CY2020Q4	qlys	Availableforsale Securities Debt Maturities Next Twelve Months Fair Value AvailableforsaleSecuritiesDebtMaturitiesNextTwelveMonthsFairValue	284891000	USD
CY2020Q4	qlys	Availableforsale Securities Debt Maturities Year One Through Two Fair Value AvailableforsaleSecuritiesDebtMaturitiesYearOneThroughTwoFairValue	57340000	USD
CY2020Q4	qlys	Availableforsale Securities Debt Maturities After Year Two Fair Value AvailableforsaleSecuritiesDebtMaturitiesAfterYearTwoFairValue	41118000	USD
CY2020Q4	us-gaap	Available For Sale Securities Debt Securities AvailableForSaleSecuritiesDebtSecurities	383349000	USD
CY2020Q4	us-gaap	Foreign Currency Contract Asset Fair Value Disclosure ForeignCurrencyContractAssetFairValueDisclosure	538000	USD
CY2019Q4	us-gaap	Foreign Currency Contract Asset Fair Value Disclosure ForeignCurrencyContractAssetFairValueDisclosure	942000	USD
CY2020Q4	us-gaap	Foreign Currency Contracts Liability Fair Value Disclosure ForeignCurrencyContractsLiabilityFairValueDisclosure	3877000	USD
CY2019Q4	us-gaap	Foreign Currency Contracts Liability Fair Value Disclosure ForeignCurrencyContractsLiabilityFairValueDisclosure	1074000	USD
CY2020	us-gaap	Gain Loss On Foreign Currency Derivative Instruments Not Designated As Hedging Instruments GainLossOnForeignCurrencyDerivativeInstrumentsNotDesignatedAsHedgingInstruments	-1634000	USD
CY2019	us-gaap	Gain Loss On Foreign Currency Derivative Instruments Not Designated As Hedging Instruments GainLossOnForeignCurrencyDerivativeInstrumentsNotDesignatedAsHedgingInstruments	438000	USD
CY2018	us-gaap	Gain Loss On Foreign Currency Derivative Instruments Not Designated As Hedging Instruments GainLossOnForeignCurrencyDerivativeInstrumentsNotDesignatedAsHedgingInstruments	543000	USD
CY2020	us-gaap	Other Comprehensive Income Loss Foreign Currency Transaction And Translation Adjustment Net Of Tax OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationAdjustmentNetOfTax	1894000	USD
CY2019	us-gaap	Other Comprehensive Income Loss Foreign Currency Transaction And Translation Adjustment Net Of Tax OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationAdjustmentNetOfTax	-792000	USD
CY2018	us-gaap	Other Comprehensive Income Loss Foreign Currency Transaction And Translation Adjustment Net Of Tax OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationAdjustmentNetOfTax	-1120000	USD
CY2019	us-gaap	Foreign Currency Transaction Gain Loss Before Tax ForeignCurrencyTransactionGainLossBeforeTax	-354000	USD
CY2018	us-gaap	Foreign Currency Transaction Gain Loss Before Tax ForeignCurrencyTransactionGainLossBeforeTax	-577000	USD
CY2020	us-gaap	Other Nonoperating Expense OtherNonoperatingExpense	253000	USD
CY2019	us-gaap	Other Nonoperating Expense OtherNonoperatingExpense	253000	USD
CY2018	us-gaap	Other Nonoperating Expense OtherNonoperatingExpense	224000	USD
CY2020	us-gaap	Other Nonoperating Income Expense OtherNonoperatingIncomeExpense	7000	USD
CY2019	us-gaap	Other Nonoperating Income Expense OtherNonoperatingIncomeExpense	-607000	USD
CY2018	us-gaap	Other Nonoperating Income Expense OtherNonoperatingIncomeExpense	-801000	USD
CY2020Q4	us-gaap	Property Plant And Equipment And Finance Lease Right Of Use Asset Before Accumulated Depreciation And Amortization PropertyPlantAndEquipmentAndFinanceLeaseRightOfUseAssetBeforeAccumulatedDepreciationAndAmortization	210408000	USD
CY2019Q4	us-gaap	Property Plant And Equipment And Finance Lease Right Of Use Asset Before Accumulated Depreciation And Amortization PropertyPlantAndEquipmentAndFinanceLeaseRightOfUseAssetBeforeAccumulatedDepreciationAndAmortization	183893000	USD
CY2020Q4	us-gaap	Accumulated Depreciation Depletion And Amortization Property Plant And Equipment AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment	145558000	USD
CY2019Q4	us-gaap	Accumulated Depreciation Depletion And Amortization Property Plant And Equipment AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment	123314000	USD
CY2020Q4	us-gaap	Property Plant And Equipment Net PropertyPlantAndEquipmentNet	64850000	USD
CY2019Q4	us-gaap	Property Plant And Equipment Net PropertyPlantAndEquipmentNet	60579000	USD
CY2020	qlys	Depreciation Depletion And Amortization Excluding Intangible Asset Amortization DepreciationDepletionAndAmortizationExcludingIntangibleAssetAmortization	26100000	USD
CY2019	qlys	Depreciation Depletion And Amortization Excluding Intangible Asset Amortization DepreciationDepletionAndAmortizationExcludingIntangibleAssetAmortization	24900000	USD
CY2018	qlys	Depreciation Depletion And Amortization Excluding Intangible Asset Amortization DepreciationDepletionAndAmortizationExcludingIntangibleAssetAmortization	25100000	USD
CY2020	us-gaap	Contract With Customer Liability Revenue Recognized ContractWithCustomerLiabilityRevenueRecognized	188600000	USD
CY2019	us-gaap	Contract With Customer Liability Revenue Recognized ContractWithCustomerLiabilityRevenueRecognized	160800000	USD
CY2018	us-gaap	Revenue From Contract With Customer Excluding Assessed Tax RevenueFromContractWithCustomerExcludingAssessedTax	278889000	USD
CY2020	us-gaap	Amortization Of Deferred Sales Commissions AmortizationOfDeferredSalesCommissions	3000000.0	USD
CY2019	us-gaap	Amortization Of Deferred Sales Commissions AmortizationOfDeferredSalesCommissions	2000000.0	USD
CY2020Q4	us-gaap	Revenue Remaining Performance Obligation RevenueRemainingPerformanceObligation	401000	USD
CY2020Q4	us-gaap	Revenue Remaining Performance Obligation RevenueRemainingPerformanceObligation	168000	USD
CY2020Q4	us-gaap	Revenue Remaining Performance Obligation RevenueRemainingPerformanceObligation	210782000	USD
CY2020	us-gaap	Revenue From Contract With Customer Excluding Assessed Tax RevenueFromContractWithCustomerExcludingAssessedTax	362963000	USD
CY2019	us-gaap	Revenue From Contract With Customer Excluding Assessed Tax RevenueFromContractWithCustomerExcludingAssessedTax	321607000	USD
CY2020Q4	us-gaap	Capitalized Contract Cost Net Current CapitalizedContractCostNetCurrent	3459000	USD
CY2019Q4	us-gaap	Capitalized Contract Cost Net Current CapitalizedContractCostNetCurrent	2568000	USD
CY2020Q4	us-gaap	Capitalized Contract Cost Net Noncurrent CapitalizedContractCostNetNoncurrent	6906000	USD
CY2019Q4	us-gaap	Capitalized Contract Cost Net Noncurrent CapitalizedContractCostNetNoncurrent	6454000	USD
CY2020Q4	us-gaap	Revenue Remaining Performance Obligation RevenueRemainingPerformanceObligation	103165000	USD
CY2020Q4	us-gaap	Revenue Remaining Performance Obligation RevenueRemainingPerformanceObligation	70381000	USD
CY2020Q4	us-gaap	Revenue Remaining Performance Obligation RevenueRemainingPerformanceObligation	35304000	USD
CY2020Q4	us-gaap	Revenue Remaining Performance Obligation RevenueRemainingPerformanceObligation	1363000	USD
CY2018	us-gaap	Amortization Of Deferred Sales Commissions AmortizationOfDeferredSalesCommissions	1200000	USD
CY2020	us-gaap	Capitalized Contract Cost Impairment Loss CapitalizedContractCostImpairmentLoss	0	USD
CY2018Q4	us-gaap	Goodwill Goodwill	7225000	USD
CY2019	us-gaap	Goodwill Acquired During Period GoodwillAcquiredDuringPeriod	100000	USD
CY2019	us-gaap	Goodwill Translation And Purchase Accounting Adjustments GoodwillTranslationAndPurchaseAccountingAdjustments	122000	USD
CY2019Q4	us-gaap	Goodwill Goodwill	7447000	USD
CY2020Q4	us-gaap	Finite Lived Intangible Assets Gross FiniteLivedIntangibleAssetsGross	29243000	USD
CY2020Q4	us-gaap	Finite Lived Intangible Assets Accumulated Amortization FiniteLivedIntangibleAssetsAccumulatedAmortization	17277000	USD
CY2020Q4	us-gaap	Finite Lived Intangible Assets Net FiniteLivedIntangibleAssetsNet	11966000	USD
CY2020Q4	us-gaap	Operating Lease Right Of Use Asset OperatingLeaseRightOfUseAsset	44838000	USD
CY2019Q4	us-gaap	Operating Lease Right Of Use Asset OperatingLeaseRightOfUseAsset	40551000	USD
CY2020Q4	us-gaap	Finite Lived Intangible Assets Net FiniteLivedIntangibleAssetsNet	11966000	USD
CY2020Q4	us-gaap	Intangible Assets Net Excluding Goodwill IntangibleAssetsNetExcludingGoodwill	12006000	USD
CY2019Q4	us-gaap	Finite Lived Intangible Assets Gross FiniteLivedIntangibleAssetsGross	27743000	USD
CY2019Q4	us-gaap	Finite Lived Intangible Assets Accumulated Amortization FiniteLivedIntangibleAssetsAccumulatedAmortization	10988000	USD
CY2019Q4	us-gaap	Finite Lived Intangible Assets Net FiniteLivedIntangibleAssetsNet	16755000	USD
CY2019Q4	us-gaap	Intangible Assets Net Excluding Goodwill IntangibleAssetsNetExcludingGoodwill	16795000	USD
CY2020	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	6300000	USD
CY2019	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	6100000	USD
CY2018	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	3700000	USD
CY2020Q4	us-gaap	Finite Lived Intangible Assets Amortization Expense Next Twelve Months FiniteLivedIntangibleAssetsAmortizationExpenseNextTwelveMonths	6581000	USD
CY2020Q4	us-gaap	Finite Lived Intangible Assets Amortization Expense Year Two FiniteLivedIntangibleAssetsAmortizationExpenseYearTwo	4823000	USD
CY2020Q4	us-gaap	Finite Lived Intangible Assets Amortization Expense Year Three FiniteLivedIntangibleAssetsAmortizationExpenseYearThree	350000	USD
CY2020Q4	us-gaap	Finite Lived Intangible Assets Amortization Expense Year Four FiniteLivedIntangibleAssetsAmortizationExpenseYearFour	212000	USD
CY2020Q4	us-gaap	Finance Lease Right Of Use Asset FinanceLeaseRightOfUseAsset	131000	USD
CY2019Q4	us-gaap	Finance Lease Right Of Use Asset FinanceLeaseRightOfUseAsset	1299000	USD
CY2020Q4	qlys	Lease Right Of Use Asset LeaseRightOfUseAsset	44969000	USD
CY2019Q4	qlys	Lease Right Of Use Asset LeaseRightOfUseAsset	41850000	USD
CY2020Q4	us-gaap	Operating Lease Liability Current OperatingLeaseLiabilityCurrent	11672000	USD
CY2019Q4	us-gaap	Operating Lease Liability Current OperatingLeaseLiabilityCurrent	7663000	USD
CY2020Q4	us-gaap	Finance Lease Liability Current FinanceLeaseLiabilityCurrent	64000	USD
CY2019Q4	us-gaap	Finance Lease Liability Current FinanceLeaseLiabilityCurrent	124000	USD
CY2020Q4	us-gaap	Operating Lease Liability Noncurrent OperatingLeaseLiabilityNoncurrent	45700000	USD
CY2019Q4	us-gaap	Operating Lease Liability Noncurrent OperatingLeaseLiabilityNoncurrent	44015000	USD
CY2020Q4	us-gaap	Finance Lease Liability Noncurrent FinanceLeaseLiabilityNoncurrent	0	USD
CY2019Q4	us-gaap	Finance Lease Liability Noncurrent FinanceLeaseLiabilityNoncurrent	54000	USD
CY2020Q4	qlys	Lease Liability LeaseLiability	57436000	USD
CY2019Q4	qlys	Lease Liability LeaseLiability	51856000	USD
CY2020	us-gaap	Operating Lease Expense OperatingLeaseExpense	16700000	USD
CY2019	us-gaap	Operating Lease Expense OperatingLeaseExpense	13900000	USD
CY2018	us-gaap	Operating Lease Expense OperatingLeaseExpense	9900000	USD
CY2020	us-gaap	Operating Lease Payments OperatingLeasePayments	13403000	USD
CY2019	us-gaap	Operating Lease Payments OperatingLeasePayments	9372000	USD
CY2020	us-gaap	Right Of Use Asset Obtained In Exchange For Operating Lease Liability RightOfUseAssetObtainedInExchangeForOperatingLeaseLiability	15837000	USD
CY2019	us-gaap	Right Of Use Asset Obtained In Exchange For Operating Lease Liability RightOfUseAssetObtainedInExchangeForOperatingLeaseLiability	17359000	USD
CY2020Q4	us-gaap	Lessee Operating Lease Liability Payments Due Next Twelve Months LesseeOperatingLeaseLiabilityPaymentsDueNextTwelveMonths	14186000	USD
CY2020Q4	us-gaap	Lessee Operating Lease Liability Payments Due Year Two LesseeOperatingLeaseLiabilityPaymentsDueYearTwo	13316000	USD
CY2020Q4	us-gaap	Lessee Operating Lease Liability Payments Due Year Three LesseeOperatingLeaseLiabilityPaymentsDueYearThree	11297000	USD
CY2020Q4	us-gaap	Lessee Operating Lease Liability Payments Due Year Four LesseeOperatingLeaseLiabilityPaymentsDueYearFour	10010000	USD
CY2020Q4	us-gaap	Lessee Operating Lease Liability Payments Due Year Five LesseeOperatingLeaseLiabilityPaymentsDueYearFive	6407000	USD
CY2020Q4	us-gaap	Lessee Operating Lease Liability Payments Due After Year Five LesseeOperatingLeaseLiabilityPaymentsDueAfterYearFive	10317000	USD
CY2020Q4	us-gaap	Lessee Operating Lease Liability Payments Due LesseeOperatingLeaseLiabilityPaymentsDue	65533000	USD
CY2020Q4	us-gaap	Lessee Operating Lease Liability Undiscounted Excess Amount LesseeOperatingLeaseLiabilityUndiscountedExcessAmount	8161000	USD
CY2020Q4	us-gaap	Operating Lease Liability OperatingLeaseLiability	57372000	USD
CY2020Q4	us-gaap	Operating Lease Liability Current OperatingLeaseLiabilityCurrent	11672000	USD
CY2020Q4	us-gaap	Operating Lease Liability Noncurrent OperatingLeaseLiabilityNoncurrent	45700000	USD
CY2020Q4	us-gaap	Operating Lease Weighted Average Remaining Lease Term1 OperatingLeaseWeightedAverageRemainingLeaseTerm1	P4Y1M6D
CY2019Q4	us-gaap	Operating Lease Weighted Average Remaining Lease Term1 OperatingLeaseWeightedAverageRemainingLeaseTerm1	P6Y6M
CY2020Q4	us-gaap	Finance Lease Weighted Average Remaining Lease Term1 FinanceLeaseWeightedAverageRemainingLeaseTerm1	P0Y1M6D
CY2019Q4	us-gaap	Finance Lease Weighted Average Remaining Lease Term1 FinanceLeaseWeightedAverageRemainingLeaseTerm1	P1Y3M18D
CY2020Q4	us-gaap	Operating Lease Weighted Average Discount Rate Percent OperatingLeaseWeightedAverageDiscountRatePercent	0.048	pure
CY2019Q4	us-gaap	Operating Lease Weighted Average Discount Rate Percent OperatingLeaseWeightedAverageDiscountRatePercent	0.050	pure
CY2020Q4	us-gaap	Finance Lease Weighted Average Discount Rate Percent FinanceLeaseWeightedAverageDiscountRatePercent	0.050	pure
CY2019Q4	us-gaap	Finance Lease Weighted Average Discount Rate Percent FinanceLeaseWeightedAverageDiscountRatePercent	0.050	pure
CY2020Q4	us-gaap	Purchase Obligation Due In Next Twelve Months PurchaseObligationDueInNextTwelveMonths	20131000	USD
CY2020Q4	us-gaap	Purchase Obligation Due In Second Year PurchaseObligationDueInSecondYear	6528000	USD
CY2020Q4	us-gaap	Purchase Obligation Due In Third Year PurchaseObligationDueInThirdYear	6924000	USD
CY2020Q4	us-gaap	Purchase Obligation Due In Fourth Year PurchaseObligationDueInFourthYear	7780000	USD
CY2019	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Forfeitures And Expirations In Period ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresAndExpirationsInPeriod	157489
CY2020Q4	us-gaap	Purchase Obligation Due In Fifth Year PurchaseObligationDueInFifthYear	1873000	USD
CY2012Q4	us-gaap	Preferred Stock Par Or Stated Value Per Share PreferredStockParOrStatedValuePerShare	0.001
CY2019	us-gaap	Employee Service Share Based Compensation Tax Benefit From Compensation Expense EmployeeServiceShareBasedCompensationTaxBenefitFromCompensationExpense	5500000	USD
CY2018	us-gaap	Employee Service Share Based Compensation Tax Benefit From Compensation Expense EmployeeServiceShareBasedCompensationTaxBenefitFromCompensationExpense	4800000	USD
CY2020Q4	us-gaap	Preferred Stock Shares Issued PreferredStockSharesIssued	0
CY2020	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Fair Value Assumptions Expected Dividend Rate ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate	0	pure
CY2019	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Fair Value Assumptions Expected Dividend Rate ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate	0	pure
CY2018	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Fair Value Assumptions Expected Dividend Rate ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate	0	pure
CY2020	us-gaap	Allocated Share Based Compensation Expense AllocatedShareBasedCompensationExpense	40035000	USD
CY2019	us-gaap	Allocated Share Based Compensation Expense AllocatedShareBasedCompensationExpense	34892000	USD
CY2018	us-gaap	Allocated Share Based Compensation Expense AllocatedShareBasedCompensationExpense	30090000	USD
CY2020	us-gaap	Employee Service Share Based Compensation Tax Benefit From Compensation Expense EmployeeServiceShareBasedCompensationTaxBenefitFromCompensationExpense	5500000	USD
CY2020Q4	us-gaap	Purchase Obligation PurchaseObligation	43236000	USD
CY2020Q4	us-gaap	Common Stock Capital Shares Reserved For Future Issuance CommonStockCapitalSharesReservedForFutureIssuance	9890527
CY2012Q4	us-gaap	Preferred Stock Shares Authorized PreferredStockSharesAuthorized	20000000
CY2017Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Number ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber	4495891
CY2017Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Weighted Average Exercise Price ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice	25.29
CY2017	us-gaap	Sharebased Compensation Arrangement By Sharebased Payment Award Options Outstanding Weighted Average Remaining Contractual Term2 SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsOutstandingWeightedAverageRemainingContractualTerm2	P6Y7M6D
CY2017Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Intrinsic Value ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingIntrinsicValue	153129000	USD
CY2018	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Grants In Period Gross ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross	366786
CY2018	us-gaap	Share Based Compensation Arrangements By Share Based Payment Award Options Grants In Period Weighted Average Exercise Price ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageExercisePrice	79.79
CY2018	us-gaap	Stock Issued During Period Shares Stock Options Exercised StockIssuedDuringPeriodSharesStockOptionsExercised	1183235
CY2018	us-gaap	Share Based Compensation Arrangements By Share Based Payment Award Options Exercises In Period Weighted Average Exercise Price ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice	20.33
CY2018	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Forfeitures And Expirations In Period ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresAndExpirationsInPeriod	250133
CY2018	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Forfeitures And Expirations In Period Weighted Average Exercise Price ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresAndExpirationsInPeriodWeightedAverageExercisePrice	39.61
CY2018Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Number ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber	3429309
CY2018Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Weighted Average Exercise Price ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice	31.79
CY2018	us-gaap	Sharebased Compensation Arrangement By Sharebased Payment Award Options Outstanding Weighted Average Remaining Contractual Term2 SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsOutstandingWeightedAverageRemainingContractualTerm2	P6Y4M24D
CY2018Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Intrinsic Value ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingIntrinsicValue	149935000	USD
CY2019	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Grants In Period Gross ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross	496145
CY2019	us-gaap	Share Based Compensation Arrangements By Share Based Payment Award Options Grants In Period Weighted Average Exercise Price ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageExercisePrice	87.10
CY2019	us-gaap	Stock Issued During Period Shares Stock Options Exercised StockIssuedDuringPeriodSharesStockOptionsExercised	901290
CY2019	us-gaap	Share Based Compensation Arrangements By Share Based Payment Award Options Exercises In Period Weighted Average Exercise Price ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice	27.55
CY2019	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Forfeitures And Expirations In Period Weighted Average Exercise Price ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresAndExpirationsInPeriodWeightedAverageExercisePrice	71.04
CY2020	us-gaap	Sharebased Compensation Arrangement By Sharebased Payment Award Options Vested And Expected To Vest Exercisable Weighted Average Remaining Contractual Term1 SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsVestedAndExpectedToVestExercisableWeightedAverageRemainingContractualTerm1	P4Y8M12D
CY2020Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Vested And Expected To Vest Exercisable Aggregate Intrinsic Value ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestExercisableAggregateIntrinsicValue	112502000	USD
CY2019Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Number ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber	2866675
CY2020Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Vested And Expected To Vest Exercisable Number ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestExercisableNumber	1290452
CY2020Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Vested And Expected To Vest Exercisable Weighted Average Exercise Price ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestExercisableWeightedAverageExercisePrice	34.69
CY2019Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Weighted Average Exercise Price ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice	40.54
CY2019	us-gaap	Sharebased Compensation Arrangement By Sharebased Payment Award Options Outstanding Weighted Average Remaining Contractual Term2 SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsOutstandingWeightedAverageRemainingContractualTerm2	P6Y
CY2019Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Intrinsic Value ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingIntrinsicValue	125647000	USD
CY2020	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Grants In Period Gross ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross	593694
CY2020	us-gaap	Share Based Compensation Arrangements By Share Based Payment Award Options Grants In Period Weighted Average Exercise Price ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageExercisePrice	99.77
CY2020	us-gaap	Stock Issued During Period Shares Stock Options Exercised StockIssuedDuringPeriodSharesStockOptionsExercised	1129845
CY2020	us-gaap	Share Based Compensation Arrangements By Share Based Payment Award Options Exercises In Period Weighted Average Exercise Price ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice	30.50
CY2020	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Forfeitures And Expirations In Period ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresAndExpirationsInPeriod	115082
CY2020	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Forfeitures And Expirations In Period Weighted Average Exercise Price ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresAndExpirationsInPeriodWeightedAverageExercisePrice	87.91
CY2020Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Number ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber	2215442
CY2020Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Weighted Average Exercise Price ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice	59.07
CY2020	us-gaap	Sharebased Compensation Arrangement By Sharebased Payment Award Options Outstanding Weighted Average Remaining Contractual Term2 SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsOutstandingWeightedAverageRemainingContractualTerm2	P6Y6M
CY2020Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Intrinsic Value ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingIntrinsicValue	139121000	USD
CY2020Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Vested And Expected To Vest Outstanding Number ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestOutstandingNumber	2071441
CY2020Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Vested And Expected To Vest Outstanding Weighted Average Exercise Price ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestOutstandingWeightedAverageExercisePrice	56.39
CY2020	us-gaap	Sharebased Compensation Arrangement By Sharebased Payment Award Options Vested And Expected To Vest Outstanding Weighted Average Remaining Contractual Term1 SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsVestedAndExpectedToVestOutstandingWeightedAverageRemainingContractualTerm1	P6Y3M18D
CY2020Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Vested And Expected To Vest Outstanding Aggregate Intrinsic Value ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestOutstandingAggregateIntrinsicValue	135647000	USD
CY2020Q4	us-gaap	Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range Number Of Outstanding Options ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfOutstandingOptions	2215442
CY2020Q4	us-gaap	Sharebased Compensation Shares Authorized Under Stock Option Plans Exercise Price Range Outstanding Options Weighted Average Exercise Price Beginning Balance1 SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeOutstandingOptionsWeightedAverageExercisePriceBeginningBalance1	59.07
CY2020	us-gaap	Sharebased Compensation Shares Authorized Under Stock Option Plans Exercise Price Range Outstanding Options Weighted Average Remaining Contractual Term2 SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeOutstandingOptionsWeightedAverageRemainingContractualTerm2	P6Y6M
CY2020Q4	us-gaap	Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range Number Of Exercisable Options ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfExercisableOptions	1290452
CY2020Q4	us-gaap	Sharebased Compensation Shares Authorized Under Stock Option Plans Exercise Price Range Exercisable Options Weighted Average Exercise Price1 SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeExercisableOptionsWeightedAverageExercisePrice1	34.69
CY2020	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Grants In Period Weighted Average Grant Date Fair Value ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue	35.49
CY2019	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Grants In Period Weighted Average Grant Date Fair Value ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue	34.02
CY2018	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Grants In Period Weighted Average Grant Date Fair Value ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue	33.05
CY2020	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Exercises In Period Total Intrinsic Value ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue	77500000	USD
CY2019	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Exercises In Period Total Intrinsic Value ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue	52100000	USD
CY2018	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Exercises In Period Total Intrinsic Value ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue	71700000	USD
CY2020Q4	us-gaap	Stock Repurchase Program Authorized Amount1 StockRepurchaseProgramAuthorizedAmount1	101800000	USD
CY2020	qlys	Sharebased Compensation Percentage Of Awards Based On Achievement Of Performance Goals SharebasedCompensationPercentageOfAwardsBasedOnAchievementOfPerformanceGoals	0.50	pure
CY2020Q2	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Plan Modification Incremental Compensation Cost ShareBasedCompensationArrangementByShareBasedPaymentAwardPlanModificationIncrementalCompensationCost	7500000	USD
CY2018Q1	us-gaap	Stock Repurchase Program Authorized Amount1 StockRepurchaseProgramAuthorizedAmount1	100000000.0	USD
CY2018Q4	qlys	Stock Repurchase Program Additional Authorized Amount StockRepurchaseProgramAdditionalAuthorizedAmount	100000000.0	USD
CY2020Q2	us-gaap	Stock Repurchase Program Authorized Amount1 StockRepurchaseProgramAuthorizedAmount1	400000000.0	USD
CY2020	us-gaap	Stock Repurchased And Retired During Period Shares StockRepurchasedAndRetiredDuringPeriodShares	1292750
CY2019	us-gaap	Stock Repurchased And Retired During Period Shares StockRepurchasedAndRetiredDuringPeriodShares	1026455
CY2020	us-gaap	Stock Repurchased And Retired During Period Value StockRepurchasedAndRetiredDuringPeriodValue	126700000	USD
CY2019	us-gaap	Stock Repurchased And Retired During Period Value StockRepurchasedAndRetiredDuringPeriodValue	86400000	USD
CY2019Q4	us-gaap	Stock Repurchase Program Authorized Amount1 StockRepurchaseProgramAuthorizedAmount1	128500000	USD
CY2020	us-gaap	Income Loss From Continuing Operations Before Income Taxes Domestic IncomeLossFromContinuingOperationsBeforeIncomeTaxesDomestic	94099000	USD
CY2019	us-gaap	Income Loss From Continuing Operations Before Income Taxes Domestic IncomeLossFromContinuingOperationsBeforeIncomeTaxesDomestic	72124000	USD
CY2018	us-gaap	Income Loss From Continuing Operations Before Income Taxes Domestic IncomeLossFromContinuingOperationsBeforeIncomeTaxesDomestic	50010000	USD
CY2020	us-gaap	Income Loss From Continuing Operations Before Income Taxes Foreign IncomeLossFromContinuingOperationsBeforeIncomeTaxesForeign	7938000	USD
CY2019	us-gaap	Income Loss From Continuing Operations Before Income Taxes Foreign IncomeLossFromContinuingOperationsBeforeIncomeTaxesForeign	7859000	USD
CY2018	us-gaap	Income Loss From Continuing Operations Before Income Taxes Foreign IncomeLossFromContinuingOperationsBeforeIncomeTaxesForeign	5458000	USD
CY2020	us-gaap	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments	102037000	USD
CY2019	us-gaap	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments	79983000	USD
CY2018	us-gaap	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments	55468000	USD
CY2020	us-gaap	Deferred Federal Income Tax Expense Benefit DeferredFederalIncomeTaxExpenseBenefit	4239000	USD
CY2020	us-gaap	Current Income Tax Expense Benefit CurrentIncomeTaxExpenseBenefit	6953000	USD
CY2019	us-gaap	Current Income Tax Expense Benefit CurrentIncomeTaxExpenseBenefit	3556000	USD
CY2018	us-gaap	Current Income Tax Expense Benefit CurrentIncomeTaxExpenseBenefit	1960000	USD
CY2018	us-gaap	Deferred Income Tax Expense Benefit DeferredIncomeTaxExpenseBenefit	-3796000	USD
CY2020	us-gaap	Current Federal Tax Expense Benefit CurrentFederalTaxExpenseBenefit	1944000	USD
CY2019	us-gaap	Current Federal Tax Expense Benefit CurrentFederalTaxExpenseBenefit	-90000	USD
CY2018	us-gaap	Current Federal Tax Expense Benefit CurrentFederalTaxExpenseBenefit	-90000	USD
CY2020	us-gaap	Current State And Local Tax Expense Benefit CurrentStateAndLocalTaxExpenseBenefit	1438000	USD
CY2019	us-gaap	Current State And Local Tax Expense Benefit CurrentStateAndLocalTaxExpenseBenefit	646000	USD
CY2018	us-gaap	Current State And Local Tax Expense Benefit CurrentStateAndLocalTaxExpenseBenefit	62000	USD
CY2020	us-gaap	Current Foreign Tax Expense Benefit CurrentForeignTaxExpenseBenefit	3571000	USD
CY2019	us-gaap	Current Foreign Tax Expense Benefit CurrentForeignTaxExpenseBenefit	3000000	USD
CY2018	us-gaap	Current Foreign Tax Expense Benefit CurrentForeignTaxExpenseBenefit	1988000	USD
CY2019	us-gaap	Deferred Federal Income Tax Expense Benefit DeferredFederalIncomeTaxExpenseBenefit	7085000	USD
CY2018	us-gaap	Deferred Federal Income Tax Expense Benefit DeferredFederalIncomeTaxExpenseBenefit	-3449000	USD
CY2020	us-gaap	Deferred State And Local Income Tax Expense Benefit DeferredStateAndLocalIncomeTaxExpenseBenefit	26000	USD
CY2019	us-gaap	Deferred State And Local Income Tax Expense Benefit DeferredStateAndLocalIncomeTaxExpenseBenefit	447000	USD
CY2018	us-gaap	Deferred State And Local Income Tax Expense Benefit DeferredStateAndLocalIncomeTaxExpenseBenefit	21000	USD
CY2020	us-gaap	Deferred Foreign Income Tax Expense Benefit DeferredForeignIncomeTaxExpenseBenefit	-753000	USD
CY2019	us-gaap	Deferred Foreign Income Tax Expense Benefit DeferredForeignIncomeTaxExpenseBenefit	-441000	USD
CY2018	us-gaap	Deferred Foreign Income Tax Expense Benefit DeferredForeignIncomeTaxExpenseBenefit	-368000	USD
CY2020	us-gaap	Deferred Income Tax Expense Benefit DeferredIncomeTaxExpenseBenefit	3512000	USD
CY2019	us-gaap	Deferred Income Tax Expense Benefit DeferredIncomeTaxExpenseBenefit	7091000	USD
CY2020	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	10465000	USD
CY2019	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	10647000	USD
CY2018	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	-1836000	USD
CY2020	us-gaap	Effective Income Tax Rate Reconciliation At Federal Statutory Income Tax Rate EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate	0.210	pure
CY2019	us-gaap	Effective Income Tax Rate Reconciliation At Federal Statutory Income Tax Rate EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate	0.210	pure
CY2018	us-gaap	Effective Income Tax Rate Reconciliation At Federal Statutory Income Tax Rate EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate	0.210	pure
CY2020	us-gaap	Effective Income Tax Rate Reconciliation State And Local Income Taxes EffectiveIncomeTaxRateReconciliationStateAndLocalIncomeTaxes	0.016	pure
CY2019	us-gaap	Effective Income Tax Rate Reconciliation State And Local Income Taxes EffectiveIncomeTaxRateReconciliationStateAndLocalIncomeTaxes	0.015	pure
CY2018	us-gaap	Effective Income Tax Rate Reconciliation State And Local Income Taxes EffectiveIncomeTaxRateReconciliationStateAndLocalIncomeTaxes	-0.019	pure
CY2020	us-gaap	Effective Income Tax Rate Reconciliation Nondeductible Expense Share Based Compensation Cost EffectiveIncomeTaxRateReconciliationNondeductibleExpenseShareBasedCompensationCost	0.048	pure
CY2018	us-gaap	Effective Income Tax Rate Reconciliation Other Adjustments EffectiveIncomeTaxRateReconciliationOtherAdjustments	0.005	pure
CY2020	us-gaap	Effective Income Tax Rate Continuing Operations EffectiveIncomeTaxRateContinuingOperations	0.103	pure
CY2019	us-gaap	Effective Income Tax Rate Continuing Operations EffectiveIncomeTaxRateContinuingOperations	0.132	pure
CY2018	us-gaap	Effective Income Tax Rate Continuing Operations EffectiveIncomeTaxRateContinuingOperations	-0.033	pure
CY2019	us-gaap	Effective Income Tax Rate Reconciliation Nondeductible Expense Share Based Compensation Cost EffectiveIncomeTaxRateReconciliationNondeductibleExpenseShareBasedCompensationCost	0.040	pure
CY2018	us-gaap	Effective Income Tax Rate Reconciliation Nondeductible Expense Share Based Compensation Cost EffectiveIncomeTaxRateReconciliationNondeductibleExpenseShareBasedCompensationCost	0.058	pure
CY2020	us-gaap	Effective Income Tax Rate Reconciliation Share Based Compensation Excess Tax Benefit Percent EffectiveIncomeTaxRateReconciliationShareBasedCompensationExcessTaxBenefitPercent	-0.138	pure
CY2019	us-gaap	Effective Income Tax Rate Reconciliation Share Based Compensation Excess Tax Benefit Percent EffectiveIncomeTaxRateReconciliationShareBasedCompensationExcessTaxBenefitPercent	-0.112	pure
CY2018	us-gaap	Effective Income Tax Rate Reconciliation Share Based Compensation Excess Tax Benefit Percent EffectiveIncomeTaxRateReconciliationShareBasedCompensationExcessTaxBenefitPercent	-0.262	pure
CY2020	us-gaap	Effective Income Tax Rate Reconciliation Foreign Income Tax Rate Differential EffectiveIncomeTaxRateReconciliationForeignIncomeTaxRateDifferential	0.002	pure
CY2019	us-gaap	Effective Income Tax Rate Reconciliation Foreign Income Tax Rate Differential EffectiveIncomeTaxRateReconciliationForeignIncomeTaxRateDifferential	0.001	pure
CY2018	us-gaap	Effective Income Tax Rate Reconciliation Foreign Income Tax Rate Differential EffectiveIncomeTaxRateReconciliationForeignIncomeTaxRateDifferential	-0.002	pure
CY2020	us-gaap	Effective Income Tax Rate Reconciliation Change In Deferred Tax Assets Valuation Allowance EffectiveIncomeTaxRateReconciliationChangeInDeferredTaxAssetsValuationAllowance	0.008	pure
CY2019	us-gaap	Effective Income Tax Rate Reconciliation Change In Deferred Tax Assets Valuation Allowance EffectiveIncomeTaxRateReconciliationChangeInDeferredTaxAssetsValuationAllowance	0.011	pure
CY2018	us-gaap	Effective Income Tax Rate Reconciliation Change In Deferred Tax Assets Valuation Allowance EffectiveIncomeTaxRateReconciliationChangeInDeferredTaxAssetsValuationAllowance	0.044	pure
CY2020	us-gaap	Effective Income Tax Rate Reconciliation Deductions Extraterritorial Income Exclusion EffectiveIncomeTaxRateReconciliationDeductionsExtraterritorialIncomeExclusion	0.017	pure
CY2019	us-gaap	Effective Income Tax Rate Reconciliation Deductions Extraterritorial Income Exclusion EffectiveIncomeTaxRateReconciliationDeductionsExtraterritorialIncomeExclusion	-0	pure
CY2018	us-gaap	Effective Income Tax Rate Reconciliation Deductions Extraterritorial Income Exclusion EffectiveIncomeTaxRateReconciliationDeductionsExtraterritorialIncomeExclusion	-0	pure
CY2020	us-gaap	Effective Income Tax Rate Reconciliation Tax Credits Research EffectiveIncomeTaxRateReconciliationTaxCreditsResearch	0.026	pure
CY2019	us-gaap	Effective Income Tax Rate Reconciliation Tax Credits Research EffectiveIncomeTaxRateReconciliationTaxCreditsResearch	0.037	pure
CY2018	us-gaap	Effective Income Tax Rate Reconciliation Tax Credits Research EffectiveIncomeTaxRateReconciliationTaxCreditsResearch	0.067	pure
CY2020	us-gaap	Effective Income Tax Rate Reconciliation Other Adjustments EffectiveIncomeTaxRateReconciliationOtherAdjustments	0	pure
CY2019	us-gaap	Effective Income Tax Rate Reconciliation Other Adjustments EffectiveIncomeTaxRateReconciliationOtherAdjustments	0.004	pure
CY2020Q4	us-gaap	Deferred Tax Assets Operating Loss Carryforwards DeferredTaxAssetsOperatingLossCarryforwards	290000	USD
CY2019Q4	us-gaap	Deferred Tax Assets Operating Loss Carryforwards DeferredTaxAssetsOperatingLossCarryforwards	1325000	USD
CY2020Q4	us-gaap	Deferred Tax Assets Tax Credit Carryforwards Research DeferredTaxAssetsTaxCreditCarryforwardsResearch	16965000	USD
CY2019Q4	us-gaap	Deferred Tax Assets Tax Credit Carryforwards Research DeferredTaxAssetsTaxCreditCarryforwardsResearch	20182000	USD
CY2020Q4	us-gaap	Deferred Tax Assets Tax Credit Carryforwards Foreign DeferredTaxAssetsTaxCreditCarryforwardsForeign	3497000	USD
CY2019Q4	us-gaap	Deferred Tax Assets Tax Credit Carryforwards Foreign DeferredTaxAssetsTaxCreditCarryforwardsForeign	2586000	USD
CY2020Q4	us-gaap	Deferred Tax Assets Tax Deferred Expense Reserves And Accruals Accrued Liabilities DeferredTaxAssetsTaxDeferredExpenseReservesAndAccrualsAccruedLiabilities	2019000	USD
CY2019Q4	us-gaap	Deferred Tax Assets Tax Deferred Expense Reserves And Accruals Accrued Liabilities DeferredTaxAssetsTaxDeferredExpenseReservesAndAccrualsAccruedLiabilities	1109000	USD
CY2020Q4	us-gaap	Deferred Tax Assets Deferred Income DeferredTaxAssetsDeferredIncome	5123000	USD
CY2019Q4	us-gaap	Deferred Tax Assets Deferred Income DeferredTaxAssetsDeferredIncome	4843000	USD
CY2020Q4	qlys	Deferred Tax Assets Operating Lease Liabilities DeferredTaxAssetsOperatingLeaseLiabilities	15924000	USD
CY2019Q4	qlys	Deferred Tax Assets Operating Lease Liabilities DeferredTaxAssetsOperatingLeaseLiabilities	13187000	USD
CY2020Q4	us-gaap	Deferred Tax Assets Goodwill And Intangible Assets DeferredTaxAssetsGoodwillAndIntangibleAssets	1397000	USD
CY2019Q4	us-gaap	Deferred Tax Assets Goodwill And Intangible Assets DeferredTaxAssetsGoodwillAndIntangibleAssets	327000	USD
CY2020Q4	us-gaap	Deferred Tax Assets Tax Deferred Expense Compensation And Benefits Share Based Compensation Cost DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefitsShareBasedCompensationCost	3907000	USD
CY2019Q4	us-gaap	Deferred Tax Assets Tax Deferred Expense Compensation And Benefits Share Based Compensation Cost DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefitsShareBasedCompensationCost	5942000	USD
CY2020Q4	us-gaap	Deferred Tax Assets Other DeferredTaxAssetsOther	430000	USD
CY2019Q4	us-gaap	Deferred Tax Assets Other DeferredTaxAssetsOther	158000	USD
CY2017Q4	us-gaap	Unrecognized Tax Benefits UnrecognizedTaxBenefits	5112000	USD
CY2020Q4	us-gaap	Deferred Tax Assets Gross DeferredTaxAssetsGross	49552000	USD
CY2019Q4	us-gaap	Deferred Tax Assets Gross DeferredTaxAssetsGross	49659000	USD
CY2020Q4	us-gaap	Deferred Tax Assets Valuation Allowance DeferredTaxAssetsValuationAllowance	11188000	USD
CY2019Q4	us-gaap	Deferred Tax Assets Valuation Allowance DeferredTaxAssetsValuationAllowance	10094000	USD
CY2020Q4	us-gaap	Deferred Tax Assets Net DeferredTaxAssetsNet	38364000	USD
CY2019Q4	us-gaap	Deferred Tax Assets Net DeferredTaxAssetsNet	39565000	USD
CY2020Q4	us-gaap	Deferred Tax Liabilities Property Plant And Equipment DeferredTaxLiabilitiesPropertyPlantAndEquipment	7017000	USD
CY2019Q4	us-gaap	Deferred Tax Liabilities Property Plant And Equipment DeferredTaxLiabilitiesPropertyPlantAndEquipment	8097000	USD
CY2020Q4	qlys	Deferred Liabilities Rightofuse Assets DeferredLiabilitiesRightofuseAssets	13054000	USD
CY2019Q4	qlys	Deferred Liabilities Rightofuse Assets DeferredLiabilitiesRightofuseAssets	10496000	USD
CY2020Q4	qlys	Deferred Tax Liabilities Deferred Commission DeferredTaxLiabilitiesDeferredCommission	2482000	USD
CY2019Q4	qlys	Deferred Tax Liabilities Deferred Commission DeferredTaxLiabilitiesDeferredCommission	2142000	USD
CY2020Q4	us-gaap	Deferred Income Tax Liabilities DeferredIncomeTaxLiabilities	22553000	USD
CY2019Q4	us-gaap	Deferred Income Tax Liabilities DeferredIncomeTaxLiabilities	20735000	USD
CY2020Q4	us-gaap	Deferred Tax Assets Liabilities Net DeferredTaxAssetsLiabilitiesNet	15811000	USD
CY2019Q4	us-gaap	Deferred Tax Assets Liabilities Net DeferredTaxAssetsLiabilitiesNet	18830000	USD
CY2020Q4	us-gaap	Deferred Tax Assets Valuation Allowance DeferredTaxAssetsValuationAllowance	11200000	USD
CY2019Q4	us-gaap	Deferred Tax Assets Valuation Allowance DeferredTaxAssetsValuationAllowance	10100000	USD
CY2019Q4	us-gaap	Unrecognized Tax Benefits UnrecognizedTaxBenefits	7778000	USD
CY2018Q4	us-gaap	Unrecognized Tax Benefits UnrecognizedTaxBenefits	6406000	USD
CY2020	us-gaap	Unrecognized Tax Benefits Increases Resulting From Prior Period Tax Positions UnrecognizedTaxBenefitsIncreasesResultingFromPriorPeriodTaxPositions	4000	USD
CY2019	us-gaap	Unrecognized Tax Benefits Increases Resulting From Prior Period Tax Positions UnrecognizedTaxBenefitsIncreasesResultingFromPriorPeriodTaxPositions	0	USD
CY2018	us-gaap	Unrecognized Tax Benefits Increases Resulting From Prior Period Tax Positions UnrecognizedTaxBenefitsIncreasesResultingFromPriorPeriodTaxPositions	279000	USD
CY2020	us-gaap	Unrecognized Tax Benefits Decreases Resulting From Prior Period Tax Positions UnrecognizedTaxBenefitsDecreasesResultingFromPriorPeriodTaxPositions	-0	USD
CY2019	us-gaap	Unrecognized Tax Benefits Decreases Resulting From Prior Period Tax Positions UnrecognizedTaxBenefitsDecreasesResultingFromPriorPeriodTaxPositions	12000	USD
CY2018	us-gaap	Unrecognized Tax Benefits Decreases Resulting From Prior Period Tax Positions UnrecognizedTaxBenefitsDecreasesResultingFromPriorPeriodTaxPositions	227000	USD
CY2020	us-gaap	Unrecognized Tax Benefits Increases Resulting From Current Period Tax Positions UnrecognizedTaxBenefitsIncreasesResultingFromCurrentPeriodTaxPositions	1258000	USD
CY2019	us-gaap	Unrecognized Tax Benefits Increases Resulting From Current Period Tax Positions UnrecognizedTaxBenefitsIncreasesResultingFromCurrentPeriodTaxPositions	1384000	USD
CY2018	us-gaap	Unrecognized Tax Benefits Increases Resulting From Current Period Tax Positions UnrecognizedTaxBenefitsIncreasesResultingFromCurrentPeriodTaxPositions	1399000	USD
CY2020	us-gaap	Unrecognized Tax Benefits Reductions Resulting From Lapse Of Applicable Statute Of Limitations UnrecognizedTaxBenefitsReductionsResultingFromLapseOfApplicableStatuteOfLimitations	185000	USD
CY2019	us-gaap	Unrecognized Tax Benefits Reductions Resulting From Lapse Of Applicable Statute Of Limitations UnrecognizedTaxBenefitsReductionsResultingFromLapseOfApplicableStatuteOfLimitations	-0	USD
CY2018	us-gaap	Unrecognized Tax Benefits Reductions Resulting From Lapse Of Applicable Statute Of Limitations UnrecognizedTaxBenefitsReductionsResultingFromLapseOfApplicableStatuteOfLimitations	157000	USD
CY2020Q4	us-gaap	Unrecognized Tax Benefits UnrecognizedTaxBenefits	8855000	USD
CY2019Q4	us-gaap	Unrecognized Tax Benefits UnrecognizedTaxBenefits	7778000	USD
CY2018Q4	us-gaap	Unrecognized Tax Benefits UnrecognizedTaxBenefits	6406000	USD
CY2020Q4	us-gaap	Unrecognized Tax Benefits That Would Impact Effective Tax Rate UnrecognizedTaxBenefitsThatWouldImpactEffectiveTaxRate	4600000	USD
CY2019Q4	us-gaap	Unrecognized Tax Benefits That Would Impact Effective Tax Rate UnrecognizedTaxBenefitsThatWouldImpactEffectiveTaxRate	4200000	USD
CY2018Q4	us-gaap	Unrecognized Tax Benefits That Would Impact Effective Tax Rate UnrecognizedTaxBenefitsThatWouldImpactEffectiveTaxRate	3500000	USD
CY2020	us-gaap	Number Of Operating Segments NumberOfOperatingSegments	1	pure
CY2020	us-gaap	Number Of Reportable Segments NumberOfReportableSegments	1	pure
CY2020	us-gaap	Revenue From Contract With Customer Excluding Assessed Tax RevenueFromContractWithCustomerExcludingAssessedTax	362963000	USD
CY2019	us-gaap	Revenue From Contract With Customer Excluding Assessed Tax RevenueFromContractWithCustomerExcludingAssessedTax	321607000	USD
CY2018	us-gaap	Revenue From Contract With Customer Excluding Assessed Tax RevenueFromContractWithCustomerExcludingAssessedTax	278889000	USD
CY2020Q4	us-gaap	Property Plant And Equipment Net PropertyPlantAndEquipmentNet	64850000	USD
CY2019Q4	us-gaap	Property Plant And Equipment Net PropertyPlantAndEquipmentNet	60579000	USD
CY2020	us-gaap	Net Income Loss NetIncomeLoss	91572000	USD
CY2019	us-gaap	Net Income Loss NetIncomeLoss	69336000	USD
CY2018	us-gaap	Net Income Loss NetIncomeLoss	57304000	USD
CY2020	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	39167000
CY2019	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	39075000
CY2018	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	38876000
CY2020	us-gaap	Incremental Common Shares Attributable To Share Based Payment Arrangements IncrementalCommonSharesAttributableToShareBasedPaymentArrangements	1267000
CY2019	us-gaap	Incremental Common Shares Attributable To Share Based Payment Arrangements IncrementalCommonSharesAttributableToShareBasedPaymentArrangements	1807000
CY2018	us-gaap	Incremental Common Shares Attributable To Share Based Payment Arrangements IncrementalCommonSharesAttributableToShareBasedPaymentArrangements	2401000
CY2020	us-gaap	Incremental Common Shares Attributable To Call Options And Warrants IncrementalCommonSharesAttributableToCallOptionsAndWarrants	389000
CY2019	us-gaap	Incremental Common Shares Attributable To Call Options And Warrants IncrementalCommonSharesAttributableToCallOptionsAndWarrants	463000
CY2018	us-gaap	Incremental Common Shares Attributable To Call Options And Warrants IncrementalCommonSharesAttributableToCallOptionsAndWarrants	620000
CY2020	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	40823000
CY2019	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	41345000
CY2018	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	41897000
CY2020	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	2.34
CY2019	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	1.77
CY2018	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	1.47
CY2020	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	2.24
CY2019	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	1.68
CY2018	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	1.37
CY2020Q1	us-gaap	Nonoperating Income Expense NonoperatingIncomeExpense	1786000	USD
CY2020Q2	us-gaap	Nonoperating Income Expense NonoperatingIncomeExpense	1586000	USD
CY2020Q2	us-gaap	Revenues Revenues	88830000	USD
CY2020Q1	us-gaap	Revenues Revenues	86263000	USD
CY2020	us-gaap	Antidilutive Securities Excluded From Computation Of Earnings Per Share Amount AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount	700000
CY2019	us-gaap	Antidilutive Securities Excluded From Computation Of Earnings Per Share Amount AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount	487000
CY2018	us-gaap	Antidilutive Securities Excluded From Computation Of Earnings Per Share Amount AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount	199000
CY2020Q4	us-gaap	Revenues Revenues	94801000	USD
CY2020Q3	us-gaap	Revenues Revenues	93069000	USD
CY2019Q4	us-gaap	Revenues Revenues	84664000	USD
CY2019Q3	us-gaap	Revenues Revenues	82671000	USD
CY2019Q2	us-gaap	Revenues Revenues	78929000	USD
CY2019Q1	us-gaap	Revenues Revenues	75343000	USD
CY2020Q4	us-gaap	Operating Income Loss OperatingIncomeLoss	24412000	USD
CY2020Q3	us-gaap	Operating Income Loss OperatingIncomeLoss	26303000	USD
CY2020Q2	us-gaap	Operating Income Loss OperatingIncomeLoss	25508000	USD
CY2020Q1	us-gaap	Operating Income Loss OperatingIncomeLoss	20431000	USD
CY2019Q4	us-gaap	Operating Income Loss OperatingIncomeLoss	19545000	USD
CY2019Q3	us-gaap	Operating Income Loss OperatingIncomeLoss	22549000	USD
CY2019Q2	us-gaap	Operating Income Loss OperatingIncomeLoss	16108000	USD
CY2019Q1	us-gaap	Operating Income Loss OperatingIncomeLoss	14051000	USD
CY2020Q4	us-gaap	Nonoperating Income Expense NonoperatingIncomeExpense	680000	USD
CY2020Q3	us-gaap	Nonoperating Income Expense NonoperatingIncomeExpense	1331000	USD
CY2019Q4	us-gaap	Nonoperating Income Expense NonoperatingIncomeExpense	1757000	USD
CY2019Q3	us-gaap	Nonoperating Income Expense NonoperatingIncomeExpense	1786000	USD
CY2019Q2	us-gaap	Nonoperating Income Expense NonoperatingIncomeExpense	2401000	USD
CY2019Q1	us-gaap	Nonoperating Income Expense NonoperatingIncomeExpense	1786000	USD
CY2020Q4	us-gaap	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments	25092000	USD
CY2020Q3	us-gaap	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments	27634000	USD
CY2020Q2	us-gaap	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments	27094000	USD
CY2020Q1	us-gaap	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments	22217000	USD
CY2019Q4	us-gaap	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments	21302000	USD
CY2019Q3	us-gaap	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments	24335000	USD
CY2019Q2	us-gaap	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments	18509000	USD
CY2019Q1	us-gaap	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments	15837000	USD
CY2020Q4	us-gaap	Net Income Loss NetIncomeLoss	23816000	USD
CY2020Q3	us-gaap	Net Income Loss NetIncomeLoss	22743000	USD
CY2020Q2	us-gaap	Net Income Loss NetIncomeLoss	26319000	USD
CY2020Q1	us-gaap	Net Income Loss NetIncomeLoss	18694000	USD
CY2019Q4	us-gaap	Net Income Loss NetIncomeLoss	20664000	USD
CY2019Q3	us-gaap	Net Income Loss NetIncomeLoss	19174000	USD
CY2019Q2	us-gaap	Net Income Loss NetIncomeLoss	16232000	USD
CY2019Q1	us-gaap	Net Income Loss NetIncomeLoss	13266000	USD
CY2020Q4	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	0.61
CY2020Q3	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	0.58
CY2020Q1	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	0.48
CY2019Q4	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	0.53
CY2019Q3	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	0.49
CY2019Q2	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	0.41
CY2019Q1	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	0.34
CY2020Q2	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	0.67
CY2020Q4	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	0.59
CY2020Q3	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	0.56
CY2020Q2	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	0.64
CY2020Q1	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	0.46
CY2019Q4	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	0.50
CY2019Q3	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	0.47
CY2019Q2	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	0.39
CY2019Q1	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	0.32

Files In Submission

Name	View Source	Status
0001437749-21-003648-index-headers.html	Edgar Link	pending
0001437749-21-003648-index.html	Edgar Link	pending
0001437749-21-003648.txt	Edgar Link	pending
0001437749-21-003648-xbrl.zip	Edgar Link	pending
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FilingSummary.xml	Edgar Link	unprocessable
Financial_Report.xlsx	Edgar Link	pending
MetaLinks.json	Edgar Link	pending
qlys-20201231.xsd	Edgar Link	pending
qlys-20201231_cal.xml	Edgar Link	unprocessable
qlys-20201231_def.xml	Edgar Link	unprocessable
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qlys20201231_10k_htm.xml	Edgar Link	completed
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stockperformancegraph2015202.jpg	Edgar Link	pending

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$QLYS
Qualys Inc Stock $qlys

2020 Q4 Form 10-K Financial Statement

#000143774921003648 Filed on February 22, 2021

Income Statement

Balance Sheet

Cashflow Statement

Facts In Submission

Files In Submission

$QLYS Qualys Inc Stock $qlys

2020 Q4 Form 10-K Financial Statement

#000143774921003648 Filed on February 22, 2021

Income Statement

Balance Sheet

Cashflow Statement

Facts In Submission

Files In Submission

$QLYS
Qualys Inc Stock $qlys