$FSLY
Fastly, Inc. Stock $fsly

$fsly Overview Financials Valuation SEC Filings Company Website

2023 Q1 Form 10-K Financial Statement

#000151741323000035 Filed on February 27, 2023

Income Statement

Concept	2023 Q1	2022 Q4	2022
Revenue	$117.6M	$119.3M	$432.7M
YoY Change	14.83%	22.11%	22.12%
Cost Of Revenue	$57.31M	$56.74M	$222.9M
YoY Change	6.3%	18.34%	33.5%
Gross Profit	$60.25M	$62.58M	$209.8M
YoY Change	24.32%	25.74%	11.99%
Gross Profit Margin	51.25%	52.45%	48.48%
Selling, General & Admin	$70.10M	$73.85M	$300.7M
YoY Change	-1.32%	5.9%	7.58%
% of Gross Profit	116.34%	118.0%	143.33%
Research & Development	$37.43M	$37.20M	$155.3M
YoY Change	-7.43%	6.29%	22.43%
% of Gross Profit	62.12%	59.44%	74.03%
Depreciation & Amortization	$12.00M	$16.95M	$42.60M
YoY Change	21.21%	26.53%	47.92%
% of Gross Profit	19.92%	27.09%	20.31%
Operating Expenses	$107.5M	$111.0M	$456.0M
YoY Change	-3.54%	4.34%	12.21%
Operating Profit	-$47.28M	-$48.46M	-$246.2M
YoY Change	-24.97%	-14.46%	12.41%
Interest Expense	$1.213M	$1.540M	$5.887M
YoY Change	-25.22%	-247.93%	12.24%
% of Operating Profit
Other Income/Expense, Net	-$250.0K	$46.00K	-$29.00K
YoY Change	-10.39%	-77.11%	-108.15%
Pretax Income	-$44.55M	-$46.88M	-$190.7M
YoY Change	-30.63%	-18.47%	-14.35%
Income Tax	$100.0K	-$223.0K	$100.0K
% Of Pretax Income
Net Earnings	-$44.69M	-$46.65M	-$190.8M
YoY Change	-30.46%	-18.89%	-14.33%
Net Earnings / Revenue	-38.01%	-39.1%	-44.09%
Basic Earnings Per Share	-$0.36		-$1.57
Diluted Earnings Per Share	-$0.36	-$0.38	-$1.57
COMMON SHARES
Basic Shares Outstanding	125.4M shares	123.0M shares	121.7M shares
Diluted Shares Outstanding	125.4M shares		121.7M shares

Balance Sheet

Concept	2023 Q1	2022 Q4	2022
SHORT-TERM ASSETS
Cash & Short-Term Investments	$546.6M	$518.0M	$518.0M
YoY Change	-14.56%	-1.87%	-1.87%
Cash & Equivalents	$348.5M	$143.4M	$143.4M
Short-Term Investments	$198.1M	$374.6M	$374.6M
Other Short-Term Assets	$29.72M	$28.93M	$28.93M
YoY Change	25.83%	-10.03%	-10.03%
Inventory
Prepaid Expenses
Receivables	$85.34M	$89.58M	$89.58M
Other Receivables	$0.00	$0.00	$0.00
Total Short-Term Assets	$661.6M	$636.5M	$636.5M
YoY Change	-10.23%	1.89%	1.89%
LONG-TERM ASSETS
Property, Plant & Equipment	$179.9M	$248.8M	$248.8M
YoY Change	3.08%	49.03%	5.17%
Goodwill	$670.2M	$670.2M
YoY Change	5.12%	5.24%
Intangibles	$77.73M	$82.90M
YoY Change	-20.11%	-19.2%
Long-Term Investments	$117.5M	$165.1M	$165.1M
YoY Change	-70.21%	-68.78%	-68.78%
Other Assets	$94.80M	$92.62M	$92.62M
YoY Change	215.78%	214.31%	215.27%
Total Long-Term Assets	$1.201B	$1.260B	$1.260B
YoY Change	-14.07%	-17.91%	-17.91%
TOTAL ASSETS
Total Short-Term Assets	$661.6M	$636.5M	$636.5M
Total Long-Term Assets	$1.201B	$1.260B	$1.260B
Total Assets	$1.862B	$1.896B	$1.896B
YoY Change	-12.74%	-12.18%	-12.18%
SHORT-TERM LIABILITIES
YoY Change
Accounts Payable	$4.668M	$4.786M	$4.786M
YoY Change	-43.4%	-48.3%	-48.3%
Accrued Expenses	$42.31M	$61.16M	$84.19M
YoY Change	-15.21%	69.36%	25.72%
Deferred Revenue	$24.60M	$28.05M
YoY Change	-13.55%	6.15%
Short-Term Debt	$0.00	$0.00	$0.00
YoY Change
Long-Term Debt Due	$24.76M	$28.95M	$28.95M
YoY Change	-7.48%		37.06%
Total Short-Term Liabilities	$125.2M	$152.3M	$152.3M
YoY Change	-10.68%	15.51%	15.51%
LONG-TERM LIABILITIES
Long-Term Debt	$705.4M	$704.7M	$720.2M
YoY Change	-24.49%	-24.48%	-24.62%
Other Long-Term Liabilities	$6.144M	$7.076M	$68.42M
YoY Change	178.64%	173.95%	18.58%
Total Long-Term Liabilities	$711.5M	$711.8M	$788.6M
YoY Change	-24.01%	-23.94%	-22.16%
TOTAL LIABILITIES
Total Short-Term Liabilities	$125.2M	$152.3M	$152.3M
Total Long-Term Liabilities	$711.5M	$711.8M	$788.6M
Total Liabilities	$903.9M	$941.0M	$941.0M
YoY Change	-21.93%	-17.83%	-17.83%
SHAREHOLDERS EQUITY
Retained Earnings	-$746.4M	-$701.7M
YoY Change	29.77%	37.34%
Common Stock	$2.000K	$2.000K
YoY Change	0.0%	0.0%
Preferred Stock
YoY Change
Treasury Stock (at cost)
YoY Change
Treasury Stock Shares
Shareholders Equity	$958.6M	$955.2M	$955.2M
YoY Change
Total Liabilities & Shareholders Equity	$1.862B	$1.896B	$1.896B
YoY Change	-12.74%	-12.18%	-12.18%

Cashflow Statement

Concept	2023 Q1	2022 Q4	2022
OPERATING ACTIVITIES
Net Income	-$44.69M	-$46.65M	-$190.8M
YoY Change	-30.46%	-18.89%	-14.33%
Depreciation, Depletion And Amortization	$12.00M	$16.95M	$42.60M
YoY Change	21.21%	26.53%	47.92%
Cash From Operating Activities	-$8.861M	-$12.13M	-$69.63M
YoY Change	-32.82%	53.36%	80.95%
INVESTING ACTIVITIES
Capital Expenditures	$3.494M	$23.74M	$19.98M
YoY Change	46.38%	-452.83%	-42.63%
Acquisitions	$0.00		$25.90M
YoY Change	-100.0%		2115.74%
Other Investing Activities	$227.2M	$96.34M	$316.1M
YoY Change	142.05%	-192.69%	-142.48%
Cash From Investing Activities	$219.5M	$72.60M	$235.8M
YoY Change	150.37%	-165.6%	-129.67%
FINANCING ACTIVITIES
Cash Dividend Paid
YoY Change
Common Stock Issuance & Retirement, Net			$0.00
YoY Change
Debt Paid & Issued, Net
YoY Change
Cash From Financing Activities	-$5.713M	-5.012M	-$189.1M
YoY Change	-204.79%	-292.55%	-120.2%
NET CHANGE
Cash From Operating Activities	-$8.861M	-12.13M	-$69.63M
Cash From Investing Activities	$219.5M	72.60M	$235.8M
Cash From Financing Activities	-$5.713M	-5.012M	-$189.1M
Net Change In Cash	$205.1M	55.46M	-$23.42M
YoY Change	157.22%	-147.82%	-122.72%
FREE CASH FLOW
Cash From Operating Activities	-$8.861M	-$12.13M	-$69.63M
Capital Expenditures	$3.494M	$23.74M	$19.98M
Free Cash Flow	-$12.36M	-$35.87M	-$89.61M
YoY Change	-20.68%	2942.41%	22.25%

Facts In Submission

Frame	Concept Type	Concept / XBRL Key	Value	Unit
CY2022	dei	Entity Central Index Key EntityCentralIndexKey	0001517413
CY2022	dei	Document Fiscal Year Focus DocumentFiscalYearFocus	2022
CY2022	dei	Document Fiscal Period Focus DocumentFiscalPeriodFocus	FY
CY2022	dei	Amendment Flag AmendmentFlag	false
CY2022	us-gaap	Number Of Operating Segments NumberOfOperatingSegments	1	segment
CY2022	dei	Document Type DocumentType	10-K
CY2022	dei	Document Annual Report DocumentAnnualReport	true
CY2022	dei	Document Period End Date DocumentPeriodEndDate	2022-12-31
CY2022	dei	Current Fiscal Year End Date CurrentFiscalYearEndDate	--12-31
CY2022	dei	Document Transition Report DocumentTransitionReport	false
CY2022	dei	Entity File Number EntityFileNumber	001-38897
CY2022	dei	Entity Registrant Name EntityRegistrantName	FASTLY, INC.
CY2022	dei	Entity Incorporation State Country Code EntityIncorporationStateCountryCode	DE
CY2022	dei	Entity Tax Identification Number EntityTaxIdentificationNumber	27-5411834
CY2022	dei	Entity Address Address Line1 EntityAddressAddressLine1	475 Brannan Street, Suite 300
CY2022	dei	Entity Address City Or Town EntityAddressCityOrTown	San Francisco
CY2022	dei	Entity Address State Or Province EntityAddressStateOrProvince	CA
CY2022	dei	Entity Address Postal Zip Code EntityAddressPostalZipCode	94107
CY2022	dei	City Area Code CityAreaCode	844
CY2022	dei	Local Phone Number LocalPhoneNumber	432-7859
CY2022	dei	Security12b Title Security12bTitle	Class A Common Stock, $0.00002 par value
CY2022	dei	Trading Symbol TradingSymbol	FSLY
CY2022	dei	Security Exchange Name SecurityExchangeName	NYSE
CY2022	dei	Entity Well Known Seasoned Issuer EntityWellKnownSeasonedIssuer	Yes
CY2022	dei	Entity Voluntary Filers EntityVoluntaryFilers	No
CY2022	dei	Entity Current Reporting Status EntityCurrentReportingStatus	Yes
CY2022	dei	Entity Interactive Data Current EntityInteractiveDataCurrent	Yes
CY2022	dei	Entity Filer Category EntityFilerCategory	Large Accelerated Filer
CY2022	dei	Entity Small Business EntitySmallBusiness	false
CY2022	dei	Entity Emerging Growth Company EntityEmergingGrowthCompany	false
CY2022	dei	Icfr Auditor Attestation Flag IcfrAuditorAttestationFlag	true
CY2022	dei	Entity Shell Company EntityShellCompany	false
CY2022Q2	dei	Entity Public Float EntityPublicFloat	1300000000	usd
CY2023Q1	dei	Entity Common Stock Shares Outstanding EntityCommonStockSharesOutstanding	125400000	shares
CY2022	dei	Auditor Firm AuditorFirmId	34
CY2022	dei	Auditor Name AuditorName	Deloitte & Touche LLP
CY2022	dei	Auditor Location AuditorLocation	San Francisco, California
CY2022Q4	us-gaap	Cash And Cash Equivalents At Carrying Value CashAndCashEquivalentsAtCarryingValue	143391000	usd
CY2021Q4	us-gaap	Cash And Cash Equivalents At Carrying Value CashAndCashEquivalentsAtCarryingValue	166068000	usd
CY2022Q4	us-gaap	Available For Sale Securities Debt Securities Current AvailableForSaleSecuritiesDebtSecuritiesCurrent	374581000	usd
CY2021Q4	us-gaap	Available For Sale Securities Debt Securities Current AvailableForSaleSecuritiesDebtSecuritiesCurrent	361795000	usd
CY2022Q4	us-gaap	Allowance For Doubtful Accounts Receivable Current AllowanceForDoubtfulAccountsReceivableCurrent	5029000	usd
CY2021Q4	us-gaap	Allowance For Doubtful Accounts Receivable Current AllowanceForDoubtfulAccountsReceivableCurrent	3311000	usd
CY2022Q4	us-gaap	Accounts Receivable Net Current AccountsReceivableNetCurrent	89578000	usd
CY2021Q4	us-gaap	Accounts Receivable Net Current AccountsReceivableNetCurrent	64625000	usd
CY2022Q4	us-gaap	Prepaid Expense And Other Assets Current PrepaidExpenseAndOtherAssetsCurrent	28933000	usd
CY2021Q4	us-gaap	Prepaid Expense And Other Assets Current PrepaidExpenseAndOtherAssetsCurrent	32160000	usd
CY2022Q4	us-gaap	Assets Current AssetsCurrent	636483000	usd
CY2021Q4	us-gaap	Assets Current AssetsCurrent	624648000	usd
CY2022Q4	us-gaap	Property Plant And Equipment And Finance Lease Right Of Use Asset After Accumulated Depreciation And Amortization PropertyPlantAndEquipmentAndFinanceLeaseRightOfUseAssetAfterAccumulatedDepreciationAndAmortization	180378000	usd
CY2021Q4	us-gaap	Property Plant And Equipment And Finance Lease Right Of Use Asset After Accumulated Depreciation And Amortization PropertyPlantAndEquipmentAndFinanceLeaseRightOfUseAssetAfterAccumulatedDepreciationAndAmortization	166961000	usd
CY2022Q4	us-gaap	Operating Lease Right Of Use Asset OperatingLeaseRightOfUseAsset	68440000	usd
CY2021Q4	us-gaap	Operating Lease Right Of Use Asset OperatingLeaseRightOfUseAsset	69631000	usd
CY2022Q4	us-gaap	Goodwill Goodwill	670185000	usd
CY2021Q4	us-gaap	Goodwill Goodwill	636805000	usd
CY2022Q4	us-gaap	Intangible Assets Net Excluding Goodwill IntangibleAssetsNetExcludingGoodwill	82900000	usd
CY2021Q4	us-gaap	Intangible Assets Net Excluding Goodwill IntangibleAssetsNetExcludingGoodwill	102596000	usd
CY2022Q4	us-gaap	Available For Sale Securities Debt Securities Noncurrent AvailableForSaleSecuritiesDebtSecuritiesNoncurrent	165105000	usd
CY2021Q4	us-gaap	Available For Sale Securities Debt Securities Noncurrent AvailableForSaleSecuritiesDebtSecuritiesNoncurrent	528911000	usd
CY2022Q4	us-gaap	Other Assets Noncurrent OtherAssetsNoncurrent	92622000	usd
CY2021Q4	us-gaap	Other Assets Noncurrent OtherAssetsNoncurrent	29468000	usd
CY2022Q4	us-gaap	Assets Assets	1896113000	usd
CY2021Q4	us-gaap	Assets Assets	2159020000	usd
CY2022Q4	us-gaap	Accounts Payable Current AccountsPayableCurrent	4786000	usd
CY2021Q4	us-gaap	Accounts Payable Current AccountsPayableCurrent	9257000	usd
CY2022Q4	us-gaap	Accrued Liabilities Current AccruedLiabilitiesCurrent	61161000	usd
CY2021Q4	us-gaap	Accrued Liabilities Current AccruedLiabilitiesCurrent	36112000	usd
CY2022Q4	us-gaap	Finance Lease Liability Current FinanceLeaseLiabilityCurrent	28954000	usd
CY2021Q4	us-gaap	Finance Lease Liability Current FinanceLeaseLiabilityCurrent	21125000	usd
CY2022Q4	us-gaap	Operating Lease Liability Current OperatingLeaseLiabilityCurrent	23026000	usd
CY2021Q4	us-gaap	Operating Lease Liability Current OperatingLeaseLiabilityCurrent	20271000	usd
CY2022Q4	us-gaap	Other Liabilities Current OtherLiabilitiesCurrent	34394000	usd
CY2021Q4	us-gaap	Other Liabilities Current OtherLiabilitiesCurrent	45107000	usd
CY2022Q4	us-gaap	Liabilities Current LiabilitiesCurrent	152321000	usd
CY2021Q4	us-gaap	Liabilities Current LiabilitiesCurrent	131872000	usd
CY2022Q4	us-gaap	Long Term Debt Noncurrent LongTermDebtNoncurrent	704710000	usd
CY2021Q4	us-gaap	Long Term Debt Noncurrent LongTermDebtNoncurrent	933205000	usd
CY2022Q4	us-gaap	Finance Lease Liability Noncurrent FinanceLeaseLiabilityNoncurrent	15507000	usd
CY2021Q4	us-gaap	Finance Lease Liability Noncurrent FinanceLeaseLiabilityNoncurrent	22293000	usd
CY2022Q4	us-gaap	Operating Lease Liability Noncurrent OperatingLeaseLiabilityNoncurrent	61341000	usd
CY2021Q4	us-gaap	Operating Lease Liability Noncurrent OperatingLeaseLiabilityNoncurrent	55114000	usd
CY2022Q4	us-gaap	Other Liabilities Noncurrent OtherLiabilitiesNoncurrent	7076000	usd
CY2021Q4	us-gaap	Other Liabilities Noncurrent OtherLiabilitiesNoncurrent	2583000	usd
CY2022Q4	us-gaap	Liabilities Liabilities	940955000	usd
CY2021Q4	us-gaap	Liabilities Liabilities	1145067000	usd
CY2022Q4	us-gaap	Commitments And Contingencies CommitmentsAndContingencies		usd
CY2021Q4	us-gaap	Commitments And Contingencies CommitmentsAndContingencies		usd
CY2022Q4	us-gaap	Common Stock Par Or Stated Value Per Share CommonStockParOrStatedValuePerShare	0.00002
CY2021Q4	us-gaap	Common Stock Par Or Stated Value Per Share CommonStockParOrStatedValuePerShare	0.00002
CY2022Q4	us-gaap	Common Stock Shares Authorized CommonStockSharesAuthorized	1000000000	shares
CY2021Q4	us-gaap	Common Stock Shares Authorized CommonStockSharesAuthorized	1094129050	shares
CY2022Q4	us-gaap	Common Stock Shares Issued CommonStockSharesIssued	124336171	shares
CY2022Q4	us-gaap	Common Stock Shares Outstanding CommonStockSharesOutstanding	124336171	shares
CY2021Q4	us-gaap	Common Stock Shares Outstanding CommonStockSharesOutstanding	118810611	shares
CY2021Q4	us-gaap	Common Stock Shares Issued CommonStockSharesIssued	118810611	shares
CY2022Q4	us-gaap	Common Stock Value CommonStockValue	2000	usd
CY2021Q4	us-gaap	Common Stock Value CommonStockValue	2000	usd
CY2022Q4	us-gaap	Additional Paid In Capital AdditionalPaidInCapital	1666106000	usd
CY2021Q4	us-gaap	Additional Paid In Capital AdditionalPaidInCapital	1527468000	usd
CY2022Q4	us-gaap	Accumulated Other Comprehensive Income Loss Net Of Tax AccumulatedOtherComprehensiveIncomeLossNetOfTax	-9286000	usd
CY2021Q4	us-gaap	Accumulated Other Comprehensive Income Loss Net Of Tax AccumulatedOtherComprehensiveIncomeLossNetOfTax	-2627000	usd
CY2022Q4	us-gaap	Retained Earnings Accumulated Deficit RetainedEarningsAccumulatedDeficit	-701664000	usd
CY2021Q4	us-gaap	Retained Earnings Accumulated Deficit RetainedEarningsAccumulatedDeficit	-510890000	usd
CY2022Q4	us-gaap	Stockholders Equity StockholdersEquity	955158000	usd
CY2021Q4	us-gaap	Stockholders Equity StockholdersEquity	1013953000	usd
CY2022Q4	us-gaap	Liabilities And Stockholders Equity LiabilitiesAndStockholdersEquity	1896113000	usd
CY2021Q4	us-gaap	Liabilities And Stockholders Equity LiabilitiesAndStockholdersEquity	2159020000	usd
CY2022	us-gaap	Revenue From Contract With Customer Including Assessed Tax RevenueFromContractWithCustomerIncludingAssessedTax	432725000	usd
CY2021	us-gaap	Revenue From Contract With Customer Including Assessed Tax RevenueFromContractWithCustomerIncludingAssessedTax	354330000	usd
CY2020	us-gaap	Revenue From Contract With Customer Including Assessed Tax RevenueFromContractWithCustomerIncludingAssessedTax	290874000	usd
CY2022	us-gaap	Cost Of Revenue CostOfRevenue	222944000	usd
CY2021	us-gaap	Cost Of Revenue CostOfRevenue	167002000	usd
CY2020	us-gaap	Cost Of Revenue CostOfRevenue	120007000	usd
CY2022	us-gaap	Gross Profit GrossProfit	209781000	usd
CY2021	us-gaap	Gross Profit GrossProfit	187328000	usd
CY2020	us-gaap	Gross Profit GrossProfit	170867000	usd
CY2022	us-gaap	Research And Development Expense ResearchAndDevelopmentExpense	155308000	usd
CY2021	us-gaap	Research And Development Expense ResearchAndDevelopmentExpense	126859000	usd
CY2020	us-gaap	Research And Development Expense ResearchAndDevelopmentExpense	74814000	usd
CY2022	us-gaap	Selling And Marketing Expense SellingAndMarketingExpense	179869000	usd
CY2021	us-gaap	Selling And Marketing Expense SellingAndMarketingExpense	152645000	usd
CY2020	us-gaap	Selling And Marketing Expense SellingAndMarketingExpense	101181000	usd
CY2022	us-gaap	General And Administrative Expense GeneralAndAdministrativeExpense	120803000	usd
CY2021	us-gaap	General And Administrative Expense GeneralAndAdministrativeExpense	126845000	usd
CY2020	us-gaap	General And Administrative Expense GeneralAndAdministrativeExpense	102084000	usd
CY2022	us-gaap	Operating Expenses OperatingExpenses	455980000	usd
CY2021	us-gaap	Operating Expenses OperatingExpenses	406349000	usd
CY2020	us-gaap	Operating Expenses OperatingExpenses	278079000	usd
CY2022	us-gaap	Operating Income Loss OperatingIncomeLoss	-246199000	usd
CY2021	us-gaap	Operating Income Loss OperatingIncomeLoss	-219021000	usd
CY2020	us-gaap	Operating Income Loss OperatingIncomeLoss	-107212000	usd
CY2022	us-gaap	Gains Losses On Extinguishment Of Debt GainsLossesOnExtinguishmentOfDebt	54391000	usd
CY2021	us-gaap	Gains Losses On Extinguishment Of Debt GainsLossesOnExtinguishmentOfDebt	0	usd
CY2020	us-gaap	Gains Losses On Extinguishment Of Debt GainsLossesOnExtinguishmentOfDebt	0	usd
CY2022	us-gaap	Investment Income Interest InvestmentIncomeInterest	7044000	usd
CY2021	us-gaap	Investment Income Interest InvestmentIncomeInterest	1282000	usd
CY2020	us-gaap	Investment Income Interest InvestmentIncomeInterest	1628000	usd
CY2022	us-gaap	Interest Expense InterestExpense	5887000	usd
CY2021	us-gaap	Interest Expense InterestExpense	5245000	usd
CY2020	us-gaap	Interest Expense InterestExpense	1549000	usd
CY2022	us-gaap	Other Nonoperating Income Expense OtherNonoperatingIncomeExpense	-29000	usd
CY2021	us-gaap	Other Nonoperating Income Expense OtherNonoperatingIncomeExpense	356000	usd
CY2020	us-gaap	Other Nonoperating Income Expense OtherNonoperatingIncomeExpense	-279000	usd
CY2022	us-gaap	Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest	-190680000	usd
CY2021	us-gaap	Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest	-222628000	usd
CY2020	us-gaap	Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest	-107412000	usd
CY2022	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	94000	usd
CY2021	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	69000	usd
CY2020	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	-11480000	usd
CY2022	us-gaap	Net Income Loss NetIncomeLoss	-190774000	usd
CY2021	us-gaap	Net Income Loss NetIncomeLoss	-222697000	usd
CY2020	us-gaap	Net Income Loss NetIncomeLoss	-95932000	usd
CY2022	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	-1.57
CY2022	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	-1.57
CY2021	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	-1.92
CY2021	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	-1.92
CY2020	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	-0.93
CY2020	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	-0.93
CY2022	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	121723000	shares
CY2022	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	121723000	shares
CY2021	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	116053000	shares
CY2021	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	116053000	shares
CY2020	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	103552000	shares
CY2020	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	103552000	shares
CY2022	us-gaap	Net Income Loss NetIncomeLoss	-190774000	usd
CY2021	us-gaap	Net Income Loss NetIncomeLoss	-222697000	usd
CY2020	us-gaap	Net Income Loss NetIncomeLoss	-95932000	usd
CY2022	us-gaap	Other Comprehensive Income Foreign Currency Transaction And Translation Adjustment Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationAdjustmentNetOfTaxPortionAttributableToParent	-255000	usd
CY2021	us-gaap	Other Comprehensive Income Foreign Currency Transaction And Translation Adjustment Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationAdjustmentNetOfTaxPortionAttributableToParent	-286000	usd
CY2020	us-gaap	Other Comprehensive Income Foreign Currency Transaction And Translation Adjustment Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationAdjustmentNetOfTaxPortionAttributableToParent	-135000	usd
CY2022	us-gaap	Other Comprehensive Income Availableforsale Securities Adjustment Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeAvailableforsaleSecuritiesAdjustmentNetOfTaxPortionAttributableToParent	-6404000	usd
CY2021	us-gaap	Other Comprehensive Income Availableforsale Securities Adjustment Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeAvailableforsaleSecuritiesAdjustmentNetOfTaxPortionAttributableToParent	-2347000	usd
CY2020	us-gaap	Other Comprehensive Income Availableforsale Securities Adjustment Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeAvailableforsaleSecuritiesAdjustmentNetOfTaxPortionAttributableToParent	-55000	usd
CY2022	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent	-6659000	usd
CY2021	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent	-2633000	usd
CY2020	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent	-190000	usd
CY2022	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	-197433000	usd
CY2021	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	-225330000	usd
CY2020	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	-96122000	usd
CY2019Q4	us-gaap	Stockholders Equity StockholdersEquity	257652000	usd
CY2020	us-gaap	Stock Issued During Period Value New Issues StockIssuedDuringPeriodValueNewIssues	274177000	usd
CY2020	us-gaap	Stock Issued During Period Value Acquisitions StockIssuedDuringPeriodValueAcquisitions	622595000	usd
CY2020	fsly	Stock Awards Acquired During Period Value StockAwardsAcquiredDuringPeriodValue	1129000	usd
CY2020	fsly	Stock Issued During Period Value Acquisition Shares Held Back For Restricted Stock Awards StockIssuedDuringPeriodValueAcquisitionSharesHeldBackForRestrictedStockAwards	87714000	usd
CY2020	us-gaap	Stock Issued During Period Shares Restricted Stock Award Net Of Forfeitures StockIssuedDuringPeriodSharesRestrictedStockAwardNetOfForfeitures	112000	shares
CY2020	us-gaap	Stock Issued During Period Value Stock Options Exercised StockIssuedDuringPeriodValueStockOptionsExercised	15273000	usd
CY2020	fsly	Stock Issued During Period Value Vesting Of Early Exercised Stock Options StockIssuedDuringPeriodValueVestingOfEarlyExercisedStockOptions	467000	usd
CY2020	us-gaap	Stock Issued During Period Value Employee Stock Purchase Plan StockIssuedDuringPeriodValueEmployeeStockPurchasePlan	8193000	usd
CY2020	us-gaap	Adjustments To Additional Paid In Capital Sharebased Compensation Requisite Service Period Recognition Value AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue	66467000	usd
CY2020	us-gaap	Net Income Loss NetIncomeLoss	-95932000	usd
CY2020	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent	-190000	usd
CY2020Q4	us-gaap	Stockholders Equity StockholdersEquity	1061865000	usd
CY2021	us-gaap	Stock Issued During Period Value Stock Options Exercised StockIssuedDuringPeriodValueStockOptionsExercised	12626000	usd
CY2021	fsly	Stock Issued During Period Value Vesting Of Early Exercised Stock Options StockIssuedDuringPeriodValueVestingOfEarlyExercisedStockOptions	405000	usd
CY2021	fsly	Stock Sold During Period Value Restricted Stock Award StockSoldDuringPeriodValueRestrictedStockAward	10655000	usd
CY2021	us-gaap	Stock Issued During Period Value Employee Stock Purchase Plan StockIssuedDuringPeriodValueEmployeeStockPurchasePlan	8798000	usd
CY2021	us-gaap	Adjustments To Additional Paid In Capital Sharebased Compensation Requisite Service Period Recognition Value AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue	144934000	usd
CY2021	us-gaap	Net Income Loss NetIncomeLoss	-222697000	usd
CY2021	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent	-2633000	usd
CY2021Q4	us-gaap	Stockholders Equity StockholdersEquity	1013953000	usd
CY2021Q4	us-gaap	Stockholders Equity StockholdersEquity	1013953000	usd
CY2022	us-gaap	Stock Issued During Period Value Stock Options Exercised StockIssuedDuringPeriodValueStockOptionsExercised	5688000	usd
CY2022	us-gaap	Stock Issued During Period Value Employee Stock Purchase Plan StockIssuedDuringPeriodValueEmployeeStockPurchasePlan	4665000	usd
CY2022	us-gaap	Adjustments To Additional Paid In Capital Sharebased Compensation Requisite Service Period Recognition Value AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue	128285000	usd
CY2022	us-gaap	Net Income Loss NetIncomeLoss	-190774000	usd
CY2022	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent	-6659000	usd
CY2022Q4	us-gaap	Stockholders Equity StockholdersEquity	955158000	usd
CY2022	us-gaap	Net Income Loss NetIncomeLoss	-190774000	usd
CY2021	us-gaap	Net Income Loss NetIncomeLoss	-222697000	usd
CY2020	us-gaap	Net Income Loss NetIncomeLoss	-95932000	usd
CY2022	us-gaap	Depreciation Nonproduction DepreciationNonproduction	42619000	usd
CY2021	us-gaap	Depreciation Nonproduction DepreciationNonproduction	28799000	usd
CY2020	us-gaap	Depreciation Nonproduction DepreciationNonproduction	19979000	usd
CY2022	fsly	Amortization Of Intangible Assets Acquired AmortizationOfIntangibleAssetsAcquired	21696000	usd
CY2021	fsly	Amortization Of Intangible Assets Acquired AmortizationOfIntangibleAssetsAcquired	21238000	usd
CY2020	fsly	Amortization Of Intangible Assets Acquired AmortizationOfIntangibleAssetsAcquired	5078000	usd
CY2022	us-gaap	Operating Lease Right Of Use Asset Amortization Expense OperatingLeaseRightOfUseAssetAmortizationExpense	29714000	usd
CY2021	us-gaap	Operating Lease Right Of Use Asset Amortization Expense OperatingLeaseRightOfUseAssetAmortizationExpense	26883000	usd
CY2020	us-gaap	Operating Lease Right Of Use Asset Amortization Expense OperatingLeaseRightOfUseAssetAmortizationExpense	21765000	usd
CY2022	us-gaap	Amortization Of Financing Costs And Discounts AmortizationOfFinancingCostsAndDiscounts	3169000	usd
CY2021	us-gaap	Amortization Of Financing Costs And Discounts AmortizationOfFinancingCostsAndDiscounts	3185000	usd
CY2020	us-gaap	Amortization Of Financing Costs And Discounts AmortizationOfFinancingCostsAndDiscounts	219000	usd
CY2022	us-gaap	Capitalized Contract Cost Amortization CapitalizedContractCostAmortization	8916000	usd
CY2021	us-gaap	Capitalized Contract Cost Amortization CapitalizedContractCostAmortization	6294000	usd
CY2020	us-gaap	Capitalized Contract Cost Amortization CapitalizedContractCostAmortization	3516000	usd
CY2022	us-gaap	Share Based Compensation ShareBasedCompensation	145796000	usd
CY2021	us-gaap	Share Based Compensation ShareBasedCompensation	140488000	usd
CY2020	us-gaap	Share Based Compensation ShareBasedCompensation	64433000	usd
CY2022	us-gaap	Provision For Doubtful Accounts ProvisionForDoubtfulAccounts	2406000	usd
CY2021	us-gaap	Provision For Doubtful Accounts ProvisionForDoubtfulAccounts	196000	usd
CY2020	us-gaap	Provision For Doubtful Accounts ProvisionForDoubtfulAccounts	1719000	usd
CY2022	us-gaap	Finance Lease Interest Payment On Liability FinanceLeaseInterestPaymentOnLiability	2381000	usd
CY2021	us-gaap	Finance Lease Interest Payment On Liability FinanceLeaseInterestPaymentOnLiability	1754000	usd
CY2020	us-gaap	Finance Lease Interest Payment On Liability FinanceLeaseInterestPaymentOnLiability	688000	usd
CY2022	us-gaap	Gain Loss On Sale Of Property Plant Equipment GainLossOnSaleOfPropertyPlantEquipment	-854000	usd
CY2021	us-gaap	Gain Loss On Sale Of Property Plant Equipment GainLossOnSaleOfPropertyPlantEquipment	300000	usd
CY2020	us-gaap	Gain Loss On Sale Of Property Plant Equipment GainLossOnSaleOfPropertyPlantEquipment	-653000	usd
CY2022	us-gaap	Accretion Amortization Of Discounts And Premiums Investments AccretionAmortizationOfDiscountsAndPremiumsInvestments	-3137000	usd
CY2021	us-gaap	Accretion Amortization Of Discounts And Premiums Investments AccretionAmortizationOfDiscountsAndPremiumsInvestments	-2221000	usd
CY2020	us-gaap	Accretion Amortization Of Discounts And Premiums Investments AccretionAmortizationOfDiscountsAndPremiumsInvestments	-345000	usd
CY2022	us-gaap	Operating Lease Impairment Loss OperatingLeaseImpairmentLoss	2083000	usd
CY2021	us-gaap	Operating Lease Impairment Loss OperatingLeaseImpairmentLoss	0	usd
CY2020	us-gaap	Operating Lease Impairment Loss OperatingLeaseImpairmentLoss	0	usd
CY2022	fsly	Tax Benefit Related To Release Of Valuation Allowance TaxBenefitRelatedToReleaseOfValuationAllowance	0	usd
CY2021	fsly	Tax Benefit Related To Release Of Valuation Allowance TaxBenefitRelatedToReleaseOfValuationAllowance	0	usd
CY2020	fsly	Tax Benefit Related To Release Of Valuation Allowance TaxBenefitRelatedToReleaseOfValuationAllowance	12950000	usd
CY2022	us-gaap	Gains Losses On Extinguishment Of Debt GainsLossesOnExtinguishmentOfDebt	54391000	usd
CY2021	us-gaap	Gains Losses On Extinguishment Of Debt GainsLossesOnExtinguishmentOfDebt	0	usd
CY2020	us-gaap	Gains Losses On Extinguishment Of Debt GainsLossesOnExtinguishmentOfDebt	0	usd
CY2022	us-gaap	Other Noncash Income Expense OtherNoncashIncomeExpense	-3688000	usd
CY2021	us-gaap	Other Noncash Income Expense OtherNoncashIncomeExpense	-4000	usd
CY2020	us-gaap	Other Noncash Income Expense OtherNoncashIncomeExpense	-279000	usd
CY2022	us-gaap	Increase Decrease In Accounts Receivable IncreaseDecreaseInAccountsReceivable	27359000	usd
CY2021	us-gaap	Increase Decrease In Accounts Receivable IncreaseDecreaseInAccountsReceivable	14563000	usd
CY2020	us-gaap	Increase Decrease In Accounts Receivable IncreaseDecreaseInAccountsReceivable	9264000	usd
CY2022	us-gaap	Increase Decrease In Prepaid Deferred Expense And Other Assets IncreaseDecreaseInPrepaidDeferredExpenseAndOtherAssets	6758000	usd
CY2021	us-gaap	Increase Decrease In Prepaid Deferred Expense And Other Assets IncreaseDecreaseInPrepaidDeferredExpenseAndOtherAssets	4777000	usd
CY2020	us-gaap	Increase Decrease In Prepaid Deferred Expense And Other Assets IncreaseDecreaseInPrepaidDeferredExpenseAndOtherAssets	5550000	usd
CY2022	us-gaap	Increase Decrease In Other Operating Assets IncreaseDecreaseInOtherOperatingAssets	35396000	usd
CY2021	us-gaap	Increase Decrease In Other Operating Assets IncreaseDecreaseInOtherOperatingAssets	10423000	usd
CY2020	us-gaap	Increase Decrease In Other Operating Assets IncreaseDecreaseInOtherOperatingAssets	17162000	usd
CY2022	us-gaap	Increase Decrease In Accounts Payable IncreaseDecreaseInAccountsPayable	-4724000	usd
CY2021	us-gaap	Increase Decrease In Accounts Payable IncreaseDecreaseInAccountsPayable	146000	usd
CY2020	us-gaap	Increase Decrease In Accounts Payable IncreaseDecreaseInAccountsPayable	4059000	usd
CY2022	us-gaap	Increase Decrease In Accrued Liabilities IncreaseDecreaseInAccruedLiabilities	8289000	usd
CY2021	us-gaap	Increase Decrease In Accrued Liabilities IncreaseDecreaseInAccruedLiabilities	4261000	usd
CY2020	us-gaap	Increase Decrease In Accrued Liabilities IncreaseDecreaseInAccruedLiabilities	12992000	usd
CY2022	fsly	Increase Decrease In Operating Lease Liabilities IncreaseDecreaseInOperatingLeaseLiabilities	-27044000	usd
CY2021	fsly	Increase Decrease In Operating Lease Liabilities IncreaseDecreaseInOperatingLeaseLiabilities	-26447000	usd
CY2020	fsly	Increase Decrease In Operating Lease Liabilities IncreaseDecreaseInOperatingLeaseLiabilities	-18264000	usd
CY2022	us-gaap	Increase Decrease In Other Operating Liabilities IncreaseDecreaseInOtherOperatingLiabilities	6828000	usd
CY2021	us-gaap	Increase Decrease In Other Operating Liabilities IncreaseDecreaseInOtherOperatingLiabilities	8764000	usd
CY2020	us-gaap	Increase Decrease In Other Operating Liabilities IncreaseDecreaseInOtherOperatingLiabilities	4857000	usd
CY2022	us-gaap	Net Cash Provided By Used In Operating Activities NetCashProvidedByUsedInOperatingActivities	-69632000	usd
CY2021	us-gaap	Net Cash Provided By Used In Operating Activities NetCashProvidedByUsedInOperatingActivities	-38482000	usd
CY2020	us-gaap	Net Cash Provided By Used In Operating Activities NetCashProvidedByUsedInOperatingActivities	-19916000	usd
CY2022	us-gaap	Payments To Acquire Available For Sale Securities Debt PaymentsToAcquireAvailableForSaleSecuritiesDebt	355479000	usd
CY2021	us-gaap	Payments To Acquire Available For Sale Securities Debt PaymentsToAcquireAvailableForSaleSecuritiesDebt	928155000	usd
CY2020	us-gaap	Payments To Acquire Available For Sale Securities Debt PaymentsToAcquireAvailableForSaleSecuritiesDebt	269059000	usd
CY2022	us-gaap	Proceeds From Sale Of Available For Sale Securities Debt ProceedsFromSaleOfAvailableForSaleSecuritiesDebt	161918000	usd
CY2021	us-gaap	Proceeds From Sale Of Available For Sale Securities Debt ProceedsFromSaleOfAvailableForSaleSecuritiesDebt	66527000	usd
CY2020	us-gaap	Proceeds From Sale Of Available For Sale Securities Debt ProceedsFromSaleOfAvailableForSaleSecuritiesDebt	143241000	usd
CY2022	us-gaap	Proceeds From Maturities Prepayments And Calls Of Available For Sale Securities ProceedsFromMaturitiesPrepaymentsAndCallsOfAvailableForSaleSecurities	535040000	usd
CY2021	us-gaap	Proceeds From Maturities Prepayments And Calls Of Available For Sale Securities ProceedsFromMaturitiesPrepaymentsAndCallsOfAvailableForSaleSecurities	118085000	usd
CY2020	us-gaap	Proceeds From Maturities Prepayments And Calls Of Available For Sale Securities ProceedsFromMaturitiesPrepaymentsAndCallsOfAvailableForSaleSecurities	88719000	usd
CY2022	us-gaap	Payments To Acquire Businesses Net Of Cash Acquired PaymentsToAcquireBusinessesNetOfCashAcquired	25902000	usd
CY2021	us-gaap	Payments To Acquire Businesses Net Of Cash Acquired PaymentsToAcquireBusinessesNetOfCashAcquired	1169000	usd
CY2020	us-gaap	Payments To Acquire Businesses Net Of Cash Acquired PaymentsToAcquireBusinessesNetOfCashAcquired	200988000	usd
CY2022	fsly	Advances For Payments Of Property Plant And Equipment AdvancesForPaymentsOfPropertyPlantAndEquipment	42197000	usd
CY2021	fsly	Advances For Payments Of Property Plant And Equipment AdvancesForPaymentsOfPropertyPlantAndEquipment	0	usd
CY2020	fsly	Advances For Payments Of Property Plant And Equipment AdvancesForPaymentsOfPropertyPlantAndEquipment	0	usd
CY2022	us-gaap	Payments To Acquire Property Plant And Equipment PaymentsToAcquirePropertyPlantAndEquipment	19975000	usd
CY2021	us-gaap	Payments To Acquire Property Plant And Equipment PaymentsToAcquirePropertyPlantAndEquipment	34816000	usd
CY2020	us-gaap	Payments To Acquire Property Plant And Equipment PaymentsToAcquirePropertyPlantAndEquipment	29569000	usd
CY2022	us-gaap	Proceeds From Sale Of Property Plant And Equipment ProceedsFromSaleOfPropertyPlantAndEquipment	492000	usd
CY2021	us-gaap	Proceeds From Sale Of Property Plant And Equipment ProceedsFromSaleOfPropertyPlantAndEquipment	588000	usd
CY2020	us-gaap	Proceeds From Sale Of Property Plant And Equipment ProceedsFromSaleOfPropertyPlantAndEquipment	575000	usd
CY2022	us-gaap	Payments For Software PaymentsForSoftware	18146000	usd
CY2021	us-gaap	Payments For Software PaymentsForSoftware	13479000	usd
CY2020	us-gaap	Payments For Software PaymentsForSoftware	6131000	usd
CY2022	us-gaap	Payments To Acquire Intangible Assets PaymentsToAcquireIntangibleAssets	0	usd
CY2021	us-gaap	Payments To Acquire Intangible Assets PaymentsToAcquireIntangibleAssets	2092000	usd
CY2020	us-gaap	Payments To Acquire Intangible Assets PaymentsToAcquireIntangibleAssets	1811000	usd
CY2022	us-gaap	Net Cash Provided By Used In Investing Activities NetCashProvidedByUsedInInvestingActivities	235751000	usd
CY2021	us-gaap	Net Cash Provided By Used In Investing Activities NetCashProvidedByUsedInInvestingActivities	-794511000	usd
CY2020	us-gaap	Net Cash Provided By Used In Investing Activities NetCashProvidedByUsedInInvestingActivities	-275023000	usd
CY2022	us-gaap	Proceeds From Issuance Of Common Stock ProceedsFromIssuanceOfCommonStock	0	usd
CY2021	us-gaap	Proceeds From Issuance Of Common Stock ProceedsFromIssuanceOfCommonStock	0	usd
CY2020	us-gaap	Proceeds From Issuance Of Common Stock ProceedsFromIssuanceOfCommonStock	274896000	usd
CY2022	us-gaap	Proceeds From Convertible Debt ProceedsFromConvertibleDebt	0	usd
CY2021	us-gaap	Proceeds From Convertible Debt ProceedsFromConvertibleDebt	930775000	usd
CY2020	us-gaap	Proceeds From Convertible Debt ProceedsFromConvertibleDebt	0	usd
CY2022	us-gaap	Payments Of Debt Issuance Costs PaymentsOfDebtIssuanceCosts	0	usd
CY2021	us-gaap	Payments Of Debt Issuance Costs PaymentsOfDebtIssuanceCosts	1351000	usd
CY2020	us-gaap	Payments Of Debt Issuance Costs PaymentsOfDebtIssuanceCosts	0	usd
CY2022	us-gaap	Repayments Of Notes Payable RepaymentsOfNotesPayable	177082000	usd
CY2021	us-gaap	Repayments Of Notes Payable RepaymentsOfNotesPayable	0	usd
CY2020	us-gaap	Repayments Of Notes Payable RepaymentsOfNotesPayable	20300000	usd
CY2022	us-gaap	Finance Lease Principal Payments FinanceLeasePrincipalPayments	22532000	usd
CY2021	us-gaap	Finance Lease Principal Payments FinanceLeasePrincipalPayments	13568000	usd
CY2020	us-gaap	Finance Lease Principal Payments FinanceLeasePrincipalPayments	5773000	usd
CY2022	fsly	Proceeds From Early Sale Of Restricted Shares ProceedsFromEarlySaleOfRestrictedShares	10655000	usd
CY2021	fsly	Proceeds From Early Sale Of Restricted Shares ProceedsFromEarlySaleOfRestrictedShares	0	usd
CY2020	fsly	Proceeds From Early Sale Of Restricted Shares ProceedsFromEarlySaleOfRestrictedShares	0	usd
CY2022	fsly	Payments For Early Sale Of Restricted Shares PaymentsForEarlySaleOfRestrictedShares	10655000	usd
CY2021	fsly	Payments For Early Sale Of Restricted Shares PaymentsForEarlySaleOfRestrictedShares	0	usd
CY2020	fsly	Payments For Early Sale Of Restricted Shares PaymentsForEarlySaleOfRestrictedShares	0	usd
CY2022	us-gaap	Proceeds From Stock Plans ProceedsFromStockPlans	4777000	usd
CY2021	us-gaap	Proceeds From Stock Plans ProceedsFromStockPlans	8069000	usd
CY2020	us-gaap	Proceeds From Stock Plans ProceedsFromStockPlans	9318000	usd
CY2022	us-gaap	Proceeds From Stock Options Exercised ProceedsFromStockOptionsExercised	5688000	usd
CY2021	us-gaap	Proceeds From Stock Options Exercised ProceedsFromStockOptionsExercised	12626000	usd
CY2020	us-gaap	Proceeds From Stock Options Exercised ProceedsFromStockOptionsExercised	15273000	usd
CY2022	us-gaap	Net Cash Provided By Used In Financing Activities NetCashProvidedByUsedInFinancingActivities	-189149000	usd
CY2021	us-gaap	Net Cash Provided By Used In Financing Activities NetCashProvidedByUsedInFinancingActivities	936551000	usd
CY2020	us-gaap	Net Cash Provided By Used In Financing Activities NetCashProvidedByUsedInFinancingActivities	272739000	usd
CY2022	us-gaap	Effect Of Exchange Rate On Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents EffectOfExchangeRateOnCashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	-390000	usd
CY2021	us-gaap	Effect Of Exchange Rate On Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents EffectOfExchangeRateOnCashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	-477000	usd
CY2020	us-gaap	Effect Of Exchange Rate On Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents EffectOfExchangeRateOnCashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	-149000	usd
CY2022	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Period Increase Decrease Including Exchange Rate Effect CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect	-23420000	usd
CY2021	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Period Increase Decrease Including Exchange Rate Effect CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect	103081000	usd
CY2020	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Period Increase Decrease Including Exchange Rate Effect CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect	-22349000	usd
CY2021Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	166961000	usd
CY2020Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	63880000	usd
CY2019Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	86229000	usd
CY2022Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	143541000	usd
CY2021Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	166961000	usd
CY2020Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	63880000	usd
CY2022	us-gaap	Interest Paid Net InterestPaidNet	2656000	usd
CY2021	us-gaap	Interest Paid Net InterestPaidNet	1938000	usd
CY2020	us-gaap	Interest Paid Net InterestPaidNet	1590000	usd
CY2022	us-gaap	Income Taxes Paid Net IncomeTaxesPaidNet	250000	usd
CY2021	us-gaap	Income Taxes Paid Net IncomeTaxesPaidNet	267000	usd
CY2020	us-gaap	Income Taxes Paid Net IncomeTaxesPaidNet	1219000	usd
CY2022	us-gaap	Capital Expenditures Incurred But Not Yet Paid CapitalExpendituresIncurredButNotYetPaid	1492000	usd
CY2021	us-gaap	Capital Expenditures Incurred But Not Yet Paid CapitalExpendituresIncurredButNotYetPaid	18275000	usd
CY2020	us-gaap	Capital Expenditures Incurred But Not Yet Paid CapitalExpendituresIncurredButNotYetPaid	3184000	usd
CY2022	fsly	Vesting Of Early Exercised Stock Options VestingOfEarlyExercisedStockOptions	0	usd
CY2021	fsly	Vesting Of Early Exercised Stock Options VestingOfEarlyExercisedStockOptions	405000	usd
CY2020	fsly	Vesting Of Early Exercised Stock Options VestingOfEarlyExercisedStockOptions	467000	usd
CY2022	fsly	Cashless Exercise Of Common Stock Warrants CashlessExerciseOfCommonStockWarrants	0	usd
CY2021	fsly	Cashless Exercise Of Common Stock Warrants CashlessExerciseOfCommonStockWarrants	0	usd
CY2020	fsly	Cashless Exercise Of Common Stock Warrants CashlessExerciseOfCommonStockWarrants	1557000	usd
CY2021	fsly	Payment For Business Incurred But Not Yet Paid PaymentForBusinessIncurredButNotYetPaid	0	usd
CY2022	us-gaap	Employee Service Share Based Compensation Allocation Of Recognized Period Costs Capitalized Amount EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsCapitalizedAmount	7997000	usd
CY2021	us-gaap	Employee Service Share Based Compensation Allocation Of Recognized Period Costs Capitalized Amount EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsCapitalizedAmount	4446000	usd
CY2020	us-gaap	Employee Service Share Based Compensation Allocation Of Recognized Period Costs Capitalized Amount EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsCapitalizedAmount	2034000	usd
CY2022	us-gaap	Right Of Use Asset Obtained In Exchange For Operating Lease Liability RightOfUseAssetObtainedInExchangeForOperatingLeaseLiability	29606000	usd
CY2021	us-gaap	Right Of Use Asset Obtained In Exchange For Operating Lease Liability RightOfUseAssetObtainedInExchangeForOperatingLeaseLiability	32458000	usd
CY2020	us-gaap	Right Of Use Asset Obtained In Exchange For Operating Lease Liability RightOfUseAssetObtainedInExchangeForOperatingLeaseLiability	23827000	usd
CY2022	us-gaap	Right Of Use Asset Obtained In Exchange For Finance Lease Liability RightOfUseAssetObtainedInExchangeForFinanceLeaseLiability	23575000	usd
CY2021	us-gaap	Right Of Use Asset Obtained In Exchange For Finance Lease Liability RightOfUseAssetObtainedInExchangeForFinanceLeaseLiability	31529000	usd
CY2020	us-gaap	Right Of Use Asset Obtained In Exchange For Finance Lease Liability RightOfUseAssetObtainedInExchangeForFinanceLeaseLiability	22541000	usd
CY2022	fsly	Noncash Change In Operating Lease Assets And Liabilities NoncashChangeInOperatingLeaseAssetsAndLiabilities	3126000	usd
CY2021	fsly	Noncash Change In Operating Lease Assets And Liabilities NoncashChangeInOperatingLeaseAssetsAndLiabilities	0	usd
CY2020	fsly	Noncash Change In Operating Lease Assets And Liabilities NoncashChangeInOperatingLeaseAssetsAndLiabilities	0	usd
CY2022	us-gaap	Interest Paid Capitalized InterestPaidCapitalized	2381000	usd
CY2021	us-gaap	Interest Paid Capitalized InterestPaidCapitalized	1754000	usd
CY2020	us-gaap	Interest Paid Capitalized InterestPaidCapitalized	688000	usd
CY2022	fsly	Payment For Business Incurred But Not Yet Paid PaymentForBusinessIncurredButNotYetPaid	8000000	usd
CY2020	fsly	Payment For Business Incurred But Not Yet Paid PaymentForBusinessIncurredButNotYetPaid	0	usd
CY2022	fsly	Deployments Of Prepaid Capital Equipment DeploymentsOfPrepaidCapitalEquipment	5184000	usd
CY2021	fsly	Deployments Of Prepaid Capital Equipment DeploymentsOfPrepaidCapitalEquipment	0	usd
CY2020	fsly	Deployments Of Prepaid Capital Equipment DeploymentsOfPrepaidCapitalEquipment	0	usd
CY2022	us-gaap	Stock Issued1 StockIssued1	0	usd
CY2021	us-gaap	Stock Issued1 StockIssued1	0	usd
CY2020	us-gaap	Stock Issued1 StockIssued1	536432000	usd
CY2022	fsly	Receivable Related To Shares Of Restricted Stock ReceivableRelatedToSharesOfRestrictedStock	0	usd
CY2021	fsly	Receivable Related To Shares Of Restricted Stock ReceivableRelatedToSharesOfRestrictedStock	10655000	usd
CY2020	fsly	Receivable Related To Shares Of Restricted Stock ReceivableRelatedToSharesOfRestrictedStock	0	usd
CY2022Q4	us-gaap	Cash And Cash Equivalents At Carrying Value CashAndCashEquivalentsAtCarryingValue	143391000	usd
CY2021Q4	us-gaap	Cash And Cash Equivalents At Carrying Value CashAndCashEquivalentsAtCarryingValue	166068000	usd
CY2020Q4	us-gaap	Cash And Cash Equivalents At Carrying Value CashAndCashEquivalentsAtCarryingValue	62900000	usd
CY2022Q4	us-gaap	Restricted Cash Current RestrictedCashCurrent	150000	usd
CY2021Q4	us-gaap	Restricted Cash Current RestrictedCashCurrent	0	usd
CY2020Q4	us-gaap	Restricted Cash Current RestrictedCashCurrent	87000	usd
CY2022Q4	us-gaap	Restricted Cash Equivalents RestrictedCashEquivalents	0	usd
CY2021Q4	us-gaap	Restricted Cash Equivalents RestrictedCashEquivalents	893000	usd
CY2020Q4	us-gaap	Restricted Cash Equivalents RestrictedCashEquivalents	893000	usd
CY2022Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	143541000	usd
CY2021Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	166961000	usd
CY2020Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	63880000	usd
CY2022	us-gaap	Nature Of Operations NatureOfOperations	Nature of Business<div style="margin-bottom:12pt;text-indent:27pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">Fastly, Inc. has built an edge cloud platform that can process, serve, and secure its customer’s applications as close to their end users as possible. As of December 31, 2022, the Company's edge network spans across 79 markets around the world. The Company was incorporated in Delaware in 2011 and is headquartered in San Francisco, California.</span></div><div style="margin-bottom:12pt;text-indent:27pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">As used herein, "Fastly," "the Company," "its" and similar terms include Fastly, Inc. and its subsidiaries, unless the context indicates otherwise.</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:700;line-height:120%">Conversion of Dual Class Common Stock Structure</span></div><div style="margin-bottom:12pt;text-indent:27pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">On July 12, 2021, all outstanding shares of Class B common stock automatically converted into the same number of shares of Class A common stock (the "Conversion") pursuant to the terms of the Company's amended and restated certificate of incorporation (the "Certificate"). Upon the Conversion, outstanding options denominated in shares of Class B common stock issued under any of the Company's equity incentive plans remained unchanged, except that such options now represent the right to receive shares of Class A common stock on exercise. In accordance with the Certificate, the shares of Class B common stock that converted to Class A common stock were retired and will not be reissued by the Company.</span></div><div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:700;line-height:120%">Follow-on Public Offering</span></div><div style="text-indent:36pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">On May 26, 2020, the Company completed a follow-on public offering in which 6,900,000 shares of Class A common stock were sold, including 900,000 shares sold pursuant to the exercise by the underwriters of an option to purchase additional shares, at the public offering price of $41.50 per share. The Company received net proceeds of $274.9 million, after deducting underwriting discounts and commissions, from sales of shares in the public offering.</span></div>
CY2022Q4	fsly	Operating Markets OperatingMarkets	79	operating_market
CY2022	us-gaap	Use Of Estimates UseOfEstimates	<div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:700;line-height:120%">Use of Estimates</span></div><div style="text-indent:27pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">The preparation of consolidated financial statements in conformity with GAAP requires management to make estimates, judgments, and assumptions that affect the reported amounts of assets, liabilities, revenue, costs and expenses, and related disclosures. Actual results and outcomes could differ significantly from the Company's estimates, judgments, and assumptions. Significant estimates, judgments, and assumptions used in these financial statements include, but are not limited to, those related to revenue, accounts receivable and related reserves, internal-use software development costs, the incremental borrowing rate related to the Company’s lease liabilities,</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:700;line-height:120%"> </span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">fair value of assets acquired and liabilities assumed during business combinations, useful lives of acquired intangible assets and property and equipment, fair value of the Company's reporting unit, income tax reserves, and accounting for stock-based compensation. Estimates are periodically reviewed in light of changes in circumstances, facts, and experience. The effects of material revisions in estimates are reflected in the consolidated financial statements in the period of change and prospectively from the date of the change in estimate.</span></div><div style="text-indent:27pt"><span><br/></span></div><div style="margin-bottom:12pt;text-indent:27pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">Due to the Coronavirus (“COVID-19”) pandemic, there has been uncertainty and disruption in the global economy and financial markets. The Company is not aware of any specific event or circumstance that would require an update to its estimates or judgments or a revision of the carrying value of its assets or liabilities as of December 31, 2022. These estimates may change, as new events occur and additional information is obtained, as well as other factors related to COVID-19 that could result in material impacts to the Company's consolidated financial statements in future reporting periods.</span></div>
CY2022	us-gaap	Concentration Risk Credit Risk ConcentrationRiskCreditRisk	<div style="margin-bottom:12pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:700;line-height:120%">Concentrations of Credit Risk</span></div><div style="margin-bottom:12pt;text-indent:27pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">Financial instruments that potentially subject the Company to significant concentrations of credit risk consist primarily of cash, cash equivalents, marketable securities and accounts receivable.</span></div><div style="margin-bottom:12pt;text-indent:27pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">The Company's cash, cash equivalents, and marketable securities primarily consisted of bank deposits, money market funds, investment-grade commercial paper, corporate notes and bonds, U.S. treasury securities, municipal securities, foreign government and supranational securities and asset-backed securities held at major financial institutions that the Company believes to be of high credit standing. The primary focus of its investment strategy is to preserve capital and meet liquidity requirements. The Company's investment policy limits the amount of credit exposure with any one financial institution or commercial issuer.</span></div>Concentrations of credit risk with respect to accounts receivable are primarily limited to certain customers to which the Company makes substantial sales. The Company's customer base consists of a large number of geographically dispersed customers diversified across several industries
CY2022Q4	us-gaap	Restricted Cash RestrictedCash	200000	usd
CY2021Q4	us-gaap	Restricted Cash RestrictedCash	900000	usd
CY2022	us-gaap	Advertising Expense AdvertisingExpense	2500000	usd
CY2021	us-gaap	Advertising Expense AdvertisingExpense	2300000	usd
CY2020	us-gaap	Advertising Expense AdvertisingExpense	3800000	usd
CY2022	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Award Requisite Service Period1 ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardRequisiteServicePeriod1	P4Y
CY2022	us-gaap	Revenue From Contract With Customer Including Assessed Tax RevenueFromContractWithCustomerIncludingAssessedTax	432725000	usd
CY2021	us-gaap	Revenue From Contract With Customer Including Assessed Tax RevenueFromContractWithCustomerIncludingAssessedTax	354330000	usd
CY2020	us-gaap	Revenue From Contract With Customer Including Assessed Tax RevenueFromContractWithCustomerIncludingAssessedTax	290874000	usd
CY2022Q4	fsly	Enterprise Customer Threshold EnterpriseCustomerThreshold	100000	usd
CY2022	us-gaap	Revenue From Contract With Customer Including Assessed Tax RevenueFromContractWithCustomerIncludingAssessedTax	432725000	usd
CY2021	us-gaap	Revenue From Contract With Customer Including Assessed Tax RevenueFromContractWithCustomerIncludingAssessedTax	354330000	usd
CY2020	us-gaap	Revenue From Contract With Customer Including Assessed Tax RevenueFromContractWithCustomerIncludingAssessedTax	290874000	usd
CY2022	us-gaap	Revenue Performance Obligation Description Of Payment Terms RevenuePerformanceObligationDescriptionOfPaymentTerms	The Company's payment terms and conditions vary by contract type, and generally range from 30 to 90 days.
CY2022Q4	us-gaap	Contract With Customer Asset Net ContractWithCustomerAssetNet	19000	usd
CY2021Q4	us-gaap	Contract With Customer Asset Net ContractWithCustomerAssetNet	89000	usd
CY2022Q4	us-gaap	Contract With Customer Liability ContractWithCustomerLiability	30544000	usd
CY2021Q4	us-gaap	Contract With Customer Liability ContractWithCustomerLiability	28907000	usd
CY2022	us-gaap	Contract With Customer Liability Revenue Recognized ContractWithCustomerLiabilityRevenueRecognized	26274000	usd
CY2021	us-gaap	Contract With Customer Liability Revenue Recognized ContractWithCustomerLiabilityRevenueRecognized	15948000	usd
CY2022Q4	us-gaap	Revenue Remaining Performance Obligation RevenueRemainingPerformanceObligation	198300000	usd
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CY2022Q4	us-gaap	Revenue Remaining Performance Obligation Expected Timing Of Satisfaction Period1 RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionPeriod1	P12M
CY2022Q4	us-gaap	Capitalized Contract Cost Net Noncurrent CapitalizedContractCostNetNoncurrent	50523000	usd
CY2021Q4	us-gaap	Capitalized Contract Cost Net Noncurrent CapitalizedContractCostNetNoncurrent	23830000	usd
CY2022	us-gaap	Capitalized Contract Cost Amortization CapitalizedContractCostAmortization	8900000	usd
CY2021	us-gaap	Capitalized Contract Cost Amortization CapitalizedContractCostAmortization	6300000	usd
CY2020	us-gaap	Capitalized Contract Cost Amortization CapitalizedContractCostAmortization	3500000	usd
CY2022Q4	us-gaap	Cash And Cash Equivalents At Carrying Value CashAndCashEquivalentsAtCarryingValue	143391000	usd
CY2021Q4	us-gaap	Cash And Cash Equivalents At Carrying Value CashAndCashEquivalentsAtCarryingValue	166068000	usd
CY2022Q4	us-gaap	Available For Sale Securities Debt Securities Current AvailableForSaleSecuritiesDebtSecuritiesCurrent	374581000	usd
CY2021Q4	us-gaap	Available For Sale Securities Debt Securities Current AvailableForSaleSecuritiesDebtSecuritiesCurrent	361795000	usd
CY2022Q4	us-gaap	Available For Sale Securities Debt Securities Noncurrent AvailableForSaleSecuritiesDebtSecuritiesNoncurrent	165105000	usd
CY2021Q4	us-gaap	Available For Sale Securities Debt Securities Noncurrent AvailableForSaleSecuritiesDebtSecuritiesNoncurrent	528911000	usd
CY2022Q4	us-gaap	Available For Sale Securities Debt Securities AvailableForSaleSecuritiesDebtSecurities	539686000	usd
CY2021Q4	us-gaap	Available For Sale Securities Debt Securities AvailableForSaleSecuritiesDebtSecurities	890706000	usd
CY2022Q4	fsly	Cash Cash Equivalents And Debt Securities Available For Sale CashCashEquivalentsAndDebtSecuritiesAvailableForSale	683077000	usd
CY2021Q4	fsly	Cash Cash Equivalents And Debt Securities Available For Sale CashCashEquivalentsAndDebtSecuritiesAvailableForSale	1056774000	usd
CY2022Q4	us-gaap	Available For Sale Debt Securities Amortized Cost Basis AvailableForSaleDebtSecuritiesAmortizedCostBasis	548333000	usd
CY2022Q4	us-gaap	Available For Sale Debt Securities Accumulated Gross Unrealized Gain Before Tax AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax	0	usd
CY2022Q4	us-gaap	Available For Sale Debt Securities Accumulated Gross Unrealized Loss Before Tax AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax	8647000	usd
CY2022Q4	us-gaap	Available For Sale Securities Debt Securities AvailableForSaleSecuritiesDebtSecurities	539686000	usd
CY2021Q4	us-gaap	Available For Sale Debt Securities Amortized Cost Basis AvailableForSaleDebtSecuritiesAmortizedCostBasis	892948000	usd
CY2021Q4	us-gaap	Available For Sale Debt Securities Accumulated Gross Unrealized Gain Before Tax AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax	1000	usd
CY2021Q4	us-gaap	Available For Sale Debt Securities Accumulated Gross Unrealized Loss Before Tax AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax	2243000	usd
CY2021Q4	us-gaap	Available For Sale Securities Debt Securities AvailableForSaleSecuritiesDebtSecurities	890706000	usd
CY2022Q4	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position12 Months Or Longer Number Of Positions DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLongerNumberOfPositions	76	security
CY2021Q4	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position12 Months Or Longer Number Of Positions DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLongerNumberOfPositions	0	security
CY2022Q4	us-gaap	Cash Equivalents At Carrying Value CashEquivalentsAtCarryingValue	96875000	usd
CY2022Q4	us-gaap	Available For Sale Securities Debt Securities AvailableForSaleSecuritiesDebtSecurities	539686000	usd
CY2022Q4	us-gaap	Restricted Cash And Cash Equivalents RestrictedCashAndCashEquivalents	150000	usd
CY2022Q4	us-gaap	Assets Fair Value Disclosure AssetsFairValueDisclosure	636711000	usd
CY2021Q4	us-gaap	Cash Equivalents At Carrying Value CashEquivalentsAtCarryingValue	31294000	usd
CY2021Q4	us-gaap	Available For Sale Securities Debt Securities AvailableForSaleSecuritiesDebtSecurities	890706000	usd
CY2021Q4	us-gaap	Restricted Cash And Cash Equivalents RestrictedCashAndCashEquivalents	893000	usd
CY2021Q4	us-gaap	Assets Fair Value Disclosure AssetsFairValueDisclosure	922893000	usd
CY2022Q4	us-gaap	Restricted Cash RestrictedCash	200000	usd
CY2021Q4	us-gaap	Restricted Cash RestrictedCash	900000	usd
CY2020Q4	us-gaap	Business Combination Recognized Identifiable Assets Acquired And Liabilities Assumed Cash And Equivalents BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCashAndEquivalents	21501000	usd
CY2020Q4	us-gaap	Business Combination Recognized Identifiable Assets Acquired And Liabilities Assumed Current Assets Other BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsOther	6419000	usd
CY2020Q4	us-gaap	Business Combination Recognized Identifiable Assets Acquired And Liabilities Assumed Intangibles BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedIntangibles	124100000	usd
CY2020Q4	us-gaap	Business Combination Recognized Identifiable Assets Acquired And Liabilities Assumed Other Noncurrent Assets BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedOtherNoncurrentAssets	8094000	usd
CY2020Q4	us-gaap	Business Combination Recognized Identifiable Assets Acquired And Liabilities Assumed Assets BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedAssets	160114000	usd
CY2020Q4	us-gaap	Business Combination Recognized Identifiable Assets Acquired And Liabilities Assumed Current Liabilities BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentLiabilities	14755000	usd
CY2020Q4	us-gaap	Business Combination Recognized Identifiable Assets Acquired And Liabilities Assumed Noncurrent Liabilities BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNoncurrentLiabilities	21170000	usd
CY2020Q4	us-gaap	Business Combination Recognized Identifiable Assets Acquired And Liabilities Assumed Liabilities BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedLiabilities	35925000	usd
CY2020Q4	us-gaap	Business Combination Recognized Identifiable Assets Acquired And Liabilities Assumed Net BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNet	124189000	usd
CY2020Q4	us-gaap	Business Combination Recognized Identifiable Assets Acquired Goodwill And Liabilities Assumed Net BusinessCombinationRecognizedIdentifiableAssetsAcquiredGoodwillAndLiabilitiesAssumedNet	759393000	usd
CY2020Q4	us-gaap	Goodwill Goodwill	635204000	usd
CY2021Q4	us-gaap	Allowance For Doubtful Accounts Receivable Current AllowanceForDoubtfulAccountsReceivableCurrent	3311000	usd
CY2020Q4	us-gaap	Allowance For Doubtful Accounts Receivable Current AllowanceForDoubtfulAccountsReceivableCurrent	3248000	usd
CY2019Q4	us-gaap	Allowance For Doubtful Accounts Receivable Current AllowanceForDoubtfulAccountsReceivableCurrent	1816000	usd
CY2022	us-gaap	Provision For Doubtful Accounts ProvisionForDoubtfulAccounts	2406000	usd
CY2021	us-gaap	Provision For Doubtful Accounts ProvisionForDoubtfulAccounts	196000	usd
CY2020	us-gaap	Provision For Doubtful Accounts ProvisionForDoubtfulAccounts	1719000	usd
CY2022	us-gaap	Allowance For Doubtful Accounts Receivable Write Offs AllowanceForDoubtfulAccountsReceivableWriteOffs	688000	usd
CY2021	us-gaap	Allowance For Doubtful Accounts Receivable Write Offs AllowanceForDoubtfulAccountsReceivableWriteOffs	133000	usd
CY2020	us-gaap	Allowance For Doubtful Accounts Receivable Write Offs AllowanceForDoubtfulAccountsReceivableWriteOffs	287000	usd
CY2022Q4	us-gaap	Allowance For Doubtful Accounts Receivable Current AllowanceForDoubtfulAccountsReceivableCurrent	5029000	usd
CY2021Q4	us-gaap	Allowance For Doubtful Accounts Receivable Current AllowanceForDoubtfulAccountsReceivableCurrent	3311000	usd
CY2020Q4	us-gaap	Allowance For Doubtful Accounts Receivable Current AllowanceForDoubtfulAccountsReceivableCurrent	3248000	usd
CY2022Q4	us-gaap	Property Plant And Equipment And Finance Lease Right Of Use Asset Before Accumulated Depreciation And Amortization PropertyPlantAndEquipmentAndFinanceLeaseRightOfUseAssetBeforeAccumulatedDepreciationAndAmortization	302839000	usd
CY2021Q4	us-gaap	Property Plant And Equipment And Finance Lease Right Of Use Asset Before Accumulated Depreciation And Amortization PropertyPlantAndEquipmentAndFinanceLeaseRightOfUseAssetBeforeAccumulatedDepreciationAndAmortization	254811000	usd
CY2022Q4	us-gaap	Property Plant And Equipment And Finance Lease Right Of Use Asset Accumulated Depreciation And Amortization PropertyPlantAndEquipmentAndFinanceLeaseRightOfUseAssetAccumulatedDepreciationAndAmortization	122461000	usd
CY2021Q4	us-gaap	Property Plant And Equipment And Finance Lease Right Of Use Asset Accumulated Depreciation And Amortization PropertyPlantAndEquipmentAndFinanceLeaseRightOfUseAssetAccumulatedDepreciationAndAmortization	87850000	usd
CY2022Q4	us-gaap	Property Plant And Equipment And Finance Lease Right Of Use Asset After Accumulated Depreciation And Amortization PropertyPlantAndEquipmentAndFinanceLeaseRightOfUseAssetAfterAccumulatedDepreciationAndAmortization	180378000	usd
CY2021Q4	us-gaap	Property Plant And Equipment And Finance Lease Right Of Use Asset After Accumulated Depreciation And Amortization PropertyPlantAndEquipmentAndFinanceLeaseRightOfUseAssetAfterAccumulatedDepreciationAndAmortization	166961000	usd
CY2022	us-gaap	Depreciation Depreciation	42600000	usd
CY2021	us-gaap	Depreciation Depreciation	28800000	usd
CY2020	us-gaap	Depreciation Depreciation	19800000	usd
CY2022Q4	us-gaap	Finance Lease Right Of Use Asset Before Accumulated Amortization FinanceLeaseRightOfUseAssetBeforeAccumulatedAmortization	77300000	usd
CY2021Q4	us-gaap	Finance Lease Right Of Use Asset Before Accumulated Amortization FinanceLeaseRightOfUseAssetBeforeAccumulatedAmortization	67800000	usd
CY2022Q4	us-gaap	Finance Lease Right Of Use Asset Accumulated Amortization FinanceLeaseRightOfUseAssetAccumulatedAmortization	28100000	usd
CY2021Q4	us-gaap	Finance Lease Right Of Use Asset Accumulated Amortization FinanceLeaseRightOfUseAssetAccumulatedAmortization	14400000	usd
CY2022Q4	us-gaap	Capitalized Contract Cost Net Noncurrent CapitalizedContractCostNetNoncurrent	50523000	usd
CY2021Q4	us-gaap	Capitalized Contract Cost Net Noncurrent CapitalizedContractCostNetNoncurrent	23830000	usd
CY2022Q4	fsly	Advances On Property And Equipment AdvancesOnPropertyAndEquipment	37013000	usd
CY2021Q4	fsly	Advances On Property And Equipment AdvancesOnPropertyAndEquipment	0	usd
CY2022Q4	us-gaap	Other Assets Miscellaneous Noncurrent OtherAssetsMiscellaneousNoncurrent	5086000	usd
CY2021Q4	us-gaap	Other Assets Miscellaneous Noncurrent OtherAssetsMiscellaneousNoncurrent	5638000	usd
CY2022Q4	us-gaap	Other Assets Noncurrent OtherAssetsNoncurrent	92622000	usd
CY2021Q4	us-gaap	Other Assets Noncurrent OtherAssetsNoncurrent	29468000	usd
CY2022Q4	us-gaap	Employee Related Liabilities Current EmployeeRelatedLiabilitiesCurrent	20204000	usd
CY2021Q4	us-gaap	Employee Related Liabilities Current EmployeeRelatedLiabilitiesCurrent	13543000	usd
CY2022Q4	us-gaap	Accrued Bonuses Current AccruedBonusesCurrent	15818000	usd
CY2021Q4	us-gaap	Accrued Bonuses Current AccruedBonusesCurrent	0	usd
CY2022Q4	fsly	Accrued Colocation And Bandwidth Costs AccruedColocationAndBandwidthCosts	10448000	usd
CY2021Q4	fsly	Accrued Colocation And Bandwidth Costs AccruedColocationAndBandwidthCosts	10205000	usd
CY2022Q4	us-gaap	Taxes Payable Current TaxesPayableCurrent	8698000	usd
CY2021Q4	us-gaap	Taxes Payable Current TaxesPayableCurrent	8070000	usd
CY2022Q4	us-gaap	Other Accrued Liabilities Current OtherAccruedLiabilitiesCurrent	5993000	usd
CY2021Q4	us-gaap	Other Accrued Liabilities Current OtherAccruedLiabilitiesCurrent	4294000	usd
CY2022Q4	us-gaap	Accrued Liabilities Current AccruedLiabilitiesCurrent	61161000	usd
CY2021Q4	us-gaap	Accrued Liabilities Current AccruedLiabilitiesCurrent	36112000	usd
CY2022Q4	us-gaap	Contract With Customer Liability Current ContractWithCustomerLiabilityCurrent	28047000	usd
CY2021Q4	us-gaap	Contract With Customer Liability Current ContractWithCustomerLiabilityCurrent	26421000	usd
CY2022Q4	fsly	Accrued Computer And Networking Equipment AccruedComputerAndNetworkingEquipment	1467000	usd
CY2021Q4	fsly	Accrued Computer And Networking Equipment AccruedComputerAndNetworkingEquipment	18081000	usd
CY2022Q4	fsly	Business Combination Consideration Transferred Holdback Current BusinessCombinationConsiderationTransferredHoldbackCurrent	4013000	usd
CY2021Q4	fsly	Business Combination Consideration Transferred Holdback Current BusinessCombinationConsiderationTransferredHoldbackCurrent	0	usd
CY2022Q4	us-gaap	Other Sundry Liabilities Current OtherSundryLiabilitiesCurrent	867000	usd
CY2021Q4	us-gaap	Other Sundry Liabilities Current OtherSundryLiabilitiesCurrent	605000	usd
CY2022Q4	us-gaap	Other Liabilities Current OtherLiabilitiesCurrent	34394000	usd
CY2021Q4	us-gaap	Other Liabilities Current OtherLiabilitiesCurrent	45107000	usd
CY2020	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent	-190000	usd
CY2021	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent	-2633000	usd
CY2022	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent	-6659000	usd
CY2022	fsly	Subleases Remaining Lease Terms SubleasesRemainingLeaseTerms	P1Y9M18D
CY2022	us-gaap	Sublease Income SubleaseIncome	900000	usd
CY2021	us-gaap	Sublease Income SubleaseIncome	1000000	usd
CY2020	us-gaap	Sublease Income SubleaseIncome	1300000	usd
CY2022	us-gaap	Operating Lease Cost OperatingLeaseCost	30976000	usd
CY2021	us-gaap	Operating Lease Cost OperatingLeaseCost	26716000	usd
CY2020	us-gaap	Operating Lease Cost OperatingLeaseCost	21765000	usd
CY2022	us-gaap	Variable Lease Cost VariableLeaseCost	11736000	usd
CY2021	us-gaap	Variable Lease Cost VariableLeaseCost	6820000	usd
CY2020	us-gaap	Variable Lease Cost VariableLeaseCost	4363000	usd
CY2022	fsly	Operating Variable And Short Term Lease Costs OperatingVariableAndShortTermLeaseCosts	42712000	usd
CY2021	fsly	Operating Variable And Short Term Lease Costs OperatingVariableAndShortTermLeaseCosts	33536000	usd
CY2020	fsly	Operating Variable And Short Term Lease Costs OperatingVariableAndShortTermLeaseCosts	26128000	usd
CY2022	us-gaap	Finance Lease Right Of Use Asset Amortization FinanceLeaseRightOfUseAssetAmortization	14539000	usd
CY2021	us-gaap	Finance Lease Right Of Use Asset Amortization FinanceLeaseRightOfUseAssetAmortization	6834000	usd
CY2020	us-gaap	Finance Lease Right Of Use Asset Amortization FinanceLeaseRightOfUseAssetAmortization	2858000	usd
CY2022	us-gaap	Finance Lease Interest Expense FinanceLeaseInterestExpense	2381000	usd
CY2021	us-gaap	Finance Lease Interest Expense FinanceLeaseInterestExpense	1754000	usd
CY2020	us-gaap	Finance Lease Interest Expense FinanceLeaseInterestExpense	688000	usd
CY2022	fsly	Finance Lease Cost FinanceLeaseCost	16920000	usd
CY2021	fsly	Finance Lease Cost FinanceLeaseCost	8588000	usd
CY2020	fsly	Finance Lease Cost FinanceLeaseCost	3546000	usd
CY2022	us-gaap	Operating Lease Impairment Loss OperatingLeaseImpairmentLoss	2100000	usd
CY2020	us-gaap	Operating Lease Impairment Loss OperatingLeaseImpairmentLoss	0	usd
CY2021	us-gaap	Operating Lease Impairment Loss OperatingLeaseImpairmentLoss	0	usd
CY2022Q4	us-gaap	Operating Lease Weighted Average Remaining Lease Term1 OperatingLeaseWeightedAverageRemainingLeaseTerm1	P4Y1M2D
CY2021Q4	us-gaap	Operating Lease Weighted Average Remaining Lease Term1 OperatingLeaseWeightedAverageRemainingLeaseTerm1	P4Y4M28D
CY2020Q4	us-gaap	Operating Lease Weighted Average Remaining Lease Term1 OperatingLeaseWeightedAverageRemainingLeaseTerm1	P4Y5M8D
CY2022Q4	us-gaap	Finance Lease Weighted Average Remaining Lease Term1 FinanceLeaseWeightedAverageRemainingLeaseTerm1	P1Y8M26D
CY2021Q4	us-gaap	Finance Lease Weighted Average Remaining Lease Term1 FinanceLeaseWeightedAverageRemainingLeaseTerm1	P2Y2M23D
CY2020Q4	us-gaap	Finance Lease Weighted Average Remaining Lease Term1 FinanceLeaseWeightedAverageRemainingLeaseTerm1	P2Y6M3D
CY2022Q4	us-gaap	Operating Lease Weighted Average Discount Rate Percent OperatingLeaseWeightedAverageDiscountRatePercent	0.0536
CY2021Q4	us-gaap	Operating Lease Weighted Average Discount Rate Percent OperatingLeaseWeightedAverageDiscountRatePercent	0.0520
CY2020Q4	us-gaap	Operating Lease Weighted Average Discount Rate Percent OperatingLeaseWeightedAverageDiscountRatePercent	0.0568
CY2022Q4	us-gaap	Finance Lease Weighted Average Discount Rate Percent FinanceLeaseWeightedAverageDiscountRatePercent	0.0473
CY2021Q4	us-gaap	Finance Lease Weighted Average Discount Rate Percent FinanceLeaseWeightedAverageDiscountRatePercent	0.0486
CY2020Q4	us-gaap	Finance Lease Weighted Average Discount Rate Percent FinanceLeaseWeightedAverageDiscountRatePercent	0.0512
CY2022Q4	us-gaap	Lessee Operating Lease Liability Payments Due Next Twelve Months LesseeOperatingLeaseLiabilityPaymentsDueNextTwelveMonths	27410000	usd
CY2022Q4	us-gaap	Finance Lease Liability Payments Due Next Twelve Months FinanceLeaseLiabilityPaymentsDueNextTwelveMonths	30285000	usd
CY2022Q4	us-gaap	Lessee Operating Lease Liability Payments Due Year Two LesseeOperatingLeaseLiabilityPaymentsDueYearTwo	20799000	usd
CY2022Q4	us-gaap	Finance Lease Liability Payments Due Year Two FinanceLeaseLiabilityPaymentsDueYearTwo	14282000	usd
CY2022Q4	us-gaap	Lessee Operating Lease Liability Payments Due Year Three LesseeOperatingLeaseLiabilityPaymentsDueYearThree	18346000	usd
CY2022Q4	us-gaap	Finance Lease Liability Payments Due Year Three FinanceLeaseLiabilityPaymentsDueYearThree	1616000	usd
CY2022Q4	us-gaap	Lessee Operating Lease Liability Payments Due Year Four LesseeOperatingLeaseLiabilityPaymentsDueYearFour	17141000	usd
CY2022Q4	us-gaap	Finance Lease Liability Payments Due Year Four FinanceLeaseLiabilityPaymentsDueYearFour	0	usd
CY2022Q4	us-gaap	Lessee Operating Lease Liability Payments Due Year Five LesseeOperatingLeaseLiabilityPaymentsDueYearFive	9820000	usd
CY2022Q4	us-gaap	Finance Lease Liability Payments Due Year Five FinanceLeaseLiabilityPaymentsDueYearFive	0	usd
CY2022Q4	us-gaap	Lessee Operating Lease Liability Payments Due After Year Five LesseeOperatingLeaseLiabilityPaymentsDueAfterYearFive	2928000	usd
CY2022Q4	us-gaap	Finance Lease Liability Payments Due After Year Five FinanceLeaseLiabilityPaymentsDueAfterYearFive	0	usd
CY2022Q4	us-gaap	Lessee Operating Lease Liability Payments Due LesseeOperatingLeaseLiabilityPaymentsDue	96444000	usd
CY2022Q4	us-gaap	Finance Lease Liability Payments Due FinanceLeaseLiabilityPaymentsDue	46183000	usd
CY2022Q4	us-gaap	Lessee Operating Lease Liability Undiscounted Excess Amount LesseeOperatingLeaseLiabilityUndiscountedExcessAmount	10195000	usd
CY2022Q4	us-gaap	Finance Lease Liability Undiscounted Excess Amount FinanceLeaseLiabilityUndiscountedExcessAmount	1722000	usd
CY2022Q4	us-gaap	Operating Lease Liability OperatingLeaseLiability	86249000	usd
CY2022Q4	us-gaap	Finance Lease Liability FinanceLeaseLiability	44461000	usd
CY2022Q4	fsly	Lessee Operating Lease Lease Not Yet Commenced Commitment Amount LesseeOperatingLeaseLeaseNotYetCommencedCommitmentAmount	1900000	usd
CY2021Q4	us-gaap	Goodwill Goodwill	636805000	usd
CY2020Q4	us-gaap	Goodwill Goodwill	635590000	usd
CY2022	us-gaap	Goodwill Acquired During Period GoodwillAcquiredDuringPeriod	33419000	usd
CY2021	us-gaap	Goodwill Acquired During Period GoodwillAcquiredDuringPeriod	1169000	usd
CY2022	us-gaap	Goodwill Foreign Currency Translation Gain Loss GoodwillForeignCurrencyTranslationGainLoss	-39000	usd
CY2021	us-gaap	Goodwill Foreign Currency Translation Gain Loss GoodwillForeignCurrencyTranslationGainLoss	46000	usd
CY2022Q4	us-gaap	Goodwill Goodwill	670185000	usd
CY2021Q4	us-gaap	Goodwill Goodwill	636805000	usd
CY2020	us-gaap	Goodwill Impairment Loss GoodwillImpairmentLoss	0	usd
CY2022	us-gaap	Goodwill Impairment Loss GoodwillImpairmentLoss	0	usd
CY2021	us-gaap	Goodwill Impairment Loss GoodwillImpairmentLoss	0	usd
CY2022Q4	us-gaap	Intangible Assets Gross Excluding Goodwill IntangibleAssetsGrossExcludingGoodwill	131084000	usd
CY2022Q4	us-gaap	Finite Lived Intangible Assets Accumulated Amortization FiniteLivedIntangibleAssetsAccumulatedAmortization	48184000	usd
CY2022Q4	us-gaap	Intangible Assets Net Excluding Goodwill IntangibleAssetsNetExcludingGoodwill	82900000	usd
CY2021Q4	us-gaap	Intangible Assets Gross Excluding Goodwill IntangibleAssetsGrossExcludingGoodwill	129491000	usd
CY2021Q4	us-gaap	Finite Lived Intangible Assets Accumulated Amortization FiniteLivedIntangibleAssetsAccumulatedAmortization	26895000	usd
CY2021Q4	us-gaap	Intangible Assets Net Excluding Goodwill IntangibleAssetsNetExcludingGoodwill	102596000	usd
CY2022	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	21700000	usd
CY2021	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	21200000	usd
CY2020	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	5300000	usd
CY2022Q4	us-gaap	Finite Lived Intangible Assets Amortization Expense Next Twelve Months FiniteLivedIntangibleAssetsAmortizationExpenseNextTwelveMonths	20424000	usd
CY2022Q4	us-gaap	Finite Lived Intangible Assets Amortization Expense Year Two FiniteLivedIntangibleAssetsAmortizationExpenseYearTwo	19599000	usd
CY2022Q4	us-gaap	Finite Lived Intangible Assets Amortization Expense Year Three FiniteLivedIntangibleAssetsAmortizationExpenseYearThree	16976000	usd
CY2022Q4	us-gaap	Finite Lived Intangible Assets Amortization Expense Year Four FiniteLivedIntangibleAssetsAmortizationExpenseYearFour	9193000	usd
CY2022Q4	us-gaap	Finite Lived Intangible Assets Amortization Expense Year Five FiniteLivedIntangibleAssetsAmortizationExpenseYearFive	9051000	usd
CY2022Q4	us-gaap	Finite Lived Intangible Assets Amortization Expense After Year Five FiniteLivedIntangibleAssetsAmortizationExpenseAfterYearFive	7657000	usd
CY2022Q4	us-gaap	Finite Lived Intangible Assets Net FiniteLivedIntangibleAssetsNet	82900000	usd
CY2022	us-gaap	Gains Losses On Extinguishment Of Debt GainsLossesOnExtinguishmentOfDebt	54400000	usd
CY2022	us-gaap	Interest Expense Debt InterestExpenseDebt	3400000	usd
CY2021	us-gaap	Interest Expense Debt InterestExpenseDebt	3500000	usd
CY2022Q4	us-gaap	Notes Payable Fair Value Disclosure NotesPayableFairValueDisclosure	517500000	usd
CY2021Q4	us-gaap	Notes Payable Fair Value Disclosure NotesPayableFairValueDisclosure	775600000	usd
CY2022Q4	us-gaap	Purchase Obligation Due In Next Twelve Months PurchaseObligationDueInNextTwelveMonths	56083000	usd
CY2022Q4	us-gaap	Purchase Obligation Due In Second Year PurchaseObligationDueInSecondYear	13661000	usd
CY2022Q4	us-gaap	Purchase Obligation Due In Third Year PurchaseObligationDueInThirdYear	654000	usd
CY2022Q4	us-gaap	Purchase Obligation Due In Fourth Year PurchaseObligationDueInFourthYear	166000	usd
CY2022Q4	us-gaap	Purchase Obligation Due In Fifth Year PurchaseObligationDueInFifthYear	77000	usd
CY2022Q4	us-gaap	Purchase Obligation Due After Fifth Year PurchaseObligationDueAfterFifthYear	14000	usd
CY2022Q4	us-gaap	Purchase Obligation PurchaseObligation	70655000	usd
CY2022	us-gaap	Long Term Purchase Commitment Amount LongTermPurchaseCommitmentAmount	11100000	usd
CY2022Q4	us-gaap	Other Commitment OtherCommitment	1200000	usd
CY2022Q4	fsly	Sales And Excise Tax Payable Current Excluding Normal Activity SalesAndExciseTaxPayableCurrentExcludingNormalActivity	7600000	usd
CY2021Q4	fsly	Sales And Excise Tax Payable Current Excluding Normal Activity SalesAndExciseTaxPayableCurrentExcludingNormalActivity	7500000	usd
CY2022	fsly	Number Of Equity Incentive Plans NumberOfEquityIncentivePlans	4	plan
CY2021Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Number ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber	4369000	shares
CY2021Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Weighted Average Exercise Price ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice	5.07
CY2021	us-gaap	Sharebased Compensation Arrangement By Sharebased Payment Award Options Outstanding Weighted Average Remaining Contractual Term2 SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsOutstandingWeightedAverageRemainingContractualTerm2	P5Y1M6D
CY2021Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Intrinsic Value ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingIntrinsicValue	132721000	usd
CY2022	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Grants In Period Gross ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross	0	shares
CY2022	us-gaap	Share Based Compensation Arrangements By Share Based Payment Award Options Grants In Period Weighted Average Exercise Price ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageExercisePrice	0
CY2022	us-gaap	Stock Issued During Period Shares Stock Options Exercised StockIssuedDuringPeriodSharesStockOptionsExercised	1778000	shares
CY2022	us-gaap	Share Based Compensation Arrangements By Share Based Payment Award Options Exercises In Period Weighted Average Exercise Price ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice	3.20
CY2022	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Forfeitures And Expirations In Period ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresAndExpirationsInPeriod	148000	shares
CY2022	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Forfeitures And Expirations In Period Weighted Average Exercise Price ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresAndExpirationsInPeriodWeightedAverageExercisePrice	12.10
CY2022Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Number ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber	2443000	shares
CY2022Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Weighted Average Exercise Price ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice	6.01
CY2022	us-gaap	Sharebased Compensation Arrangement By Sharebased Payment Award Options Outstanding Weighted Average Remaining Contractual Term2 SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsOutstandingWeightedAverageRemainingContractualTerm2	P4Y8M12D
CY2022Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Intrinsic Value ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingIntrinsicValue	7674000	usd
CY2022Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Vested And Expected To Vest Exercisable Number ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestExercisableNumber	2360000	shares
CY2022Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Vested And Expected To Vest Exercisable Weighted Average Exercise Price ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestExercisableWeightedAverageExercisePrice	5.76
CY2022	us-gaap	Sharebased Compensation Arrangement By Sharebased Payment Award Options Vested And Expected To Vest Exercisable Weighted Average Remaining Contractual Term1 SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsVestedAndExpectedToVestExercisableWeightedAverageRemainingContractualTerm1	P4Y7M6D
CY2022Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Vested And Expected To Vest Exercisable Aggregate Intrinsic Value ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestExercisableAggregateIntrinsicValue	7674000	usd
CY2022Q4	fsly	Share Based Compensation Arrangement By Share Based Payment Award Options Unvested Exercisable Number ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsUnvestedExercisableNumber	0	shares
CY2022Q4	fsly	Share Based Compensation Arrangement By Share Based Payment Award Options Unvested Exercisable Weighted Average Exercise Price ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsUnvestedExercisableWeightedAverageExercisePrice	0
CY2022	fsly	Share Based Compensation Arrangement By Share Based Payment Award Options Unvested Exercisable Weighted Average Remaining Contractual Term ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsUnvestedExercisableWeightedAverageRemainingContractualTerm	P0Y
CY2022Q4	fsly	Share Based Compensation Arrangement By Share Based Payment Award Options Unvested Exercisable Aggregate Intrinsic Value ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsUnvestedExercisableAggregateIntrinsicValue	0	usd
CY2022	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Exercises In Period Total Intrinsic Value ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue	8900000	usd
CY2021	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Exercises In Period Total Intrinsic Value ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue	64900000	usd
CY2020	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Exercises In Period Total Intrinsic Value ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue	200900000	usd
CY2022	us-gaap	Sharebased Compensation Arrangement By Sharebased Payment Award Options Vested In Period Fair Value1 SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsVestedInPeriodFairValue1	5600000	usd
CY2021	us-gaap	Sharebased Compensation Arrangement By Sharebased Payment Award Options Vested In Period Fair Value1 SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsVestedInPeriodFairValue1	6900000	usd
CY2020	us-gaap	Sharebased Compensation Arrangement By Sharebased Payment Award Options Vested In Period Fair Value1 SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsVestedInPeriodFairValue1	10300000	usd
CY2020	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Grants In Period Weighted Average Grant Date Fair Value ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue	86.77
CY2020	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Fair Value Assumptions Expected Dividend Rate ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate	0
CY2022Q4	us-gaap	Employee Service Share Based Compensation Nonvested Awards Total Compensation Cost Not Yet Recognized Stock Options EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedStockOptions	1900000	usd
CY2020Q1	fsly	Number Of Shares Issued For Each Performance Based Stock Unit NumberOfSharesIssuedForEachPerformanceBasedStockUnit	1
CY2022	us-gaap	Allocated Share Based Compensation Expense AllocatedShareBasedCompensationExpense	145796000	usd
CY2021	us-gaap	Allocated Share Based Compensation Expense AllocatedShareBasedCompensationExpense	140488000	usd
CY2020	us-gaap	Allocated Share Based Compensation Expense AllocatedShareBasedCompensationExpense	64433000	usd
CY2022	us-gaap	Employee Service Share Based Compensation Allocation Of Recognized Period Costs Capitalized Amount EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsCapitalizedAmount	8000000	usd
CY2021	us-gaap	Employee Service Share Based Compensation Allocation Of Recognized Period Costs Capitalized Amount EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsCapitalizedAmount	4400000	usd
CY2020	us-gaap	Employee Service Share Based Compensation Allocation Of Recognized Period Costs Capitalized Amount EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsCapitalizedAmount	2000000	usd
CY2022	us-gaap	Antidilutive Securities Excluded From Computation Of Earnings Per Share Amount AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount	26175000	shares
CY2021	us-gaap	Antidilutive Securities Excluded From Computation Of Earnings Per Share Amount AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount	19341000	shares
CY2020	us-gaap	Antidilutive Securities Excluded From Computation Of Earnings Per Share Amount AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount	12471000	shares
CY2022	us-gaap	Income Loss From Continuing Operations Before Income Taxes Domestic IncomeLossFromContinuingOperationsBeforeIncomeTaxesDomestic	-196469000	usd
CY2021	us-gaap	Income Loss From Continuing Operations Before Income Taxes Domestic IncomeLossFromContinuingOperationsBeforeIncomeTaxesDomestic	-224159000	usd
CY2020	us-gaap	Income Loss From Continuing Operations Before Income Taxes Domestic IncomeLossFromContinuingOperationsBeforeIncomeTaxesDomestic	-86842000	usd
CY2022	us-gaap	Income Loss From Continuing Operations Before Income Taxes Foreign IncomeLossFromContinuingOperationsBeforeIncomeTaxesForeign	5789000	usd
CY2021	us-gaap	Income Loss From Continuing Operations Before Income Taxes Foreign IncomeLossFromContinuingOperationsBeforeIncomeTaxesForeign	1531000	usd
CY2020	us-gaap	Income Loss From Continuing Operations Before Income Taxes Foreign IncomeLossFromContinuingOperationsBeforeIncomeTaxesForeign	-20570000	usd
CY2022	us-gaap	Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest	-190680000	usd
CY2021	us-gaap	Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest	-222628000	usd
CY2020	us-gaap	Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest	-107412000	usd
CY2022	us-gaap	Current Federal Tax Expense Benefit CurrentFederalTaxExpenseBenefit	0	usd
CY2021	us-gaap	Current Federal Tax Expense Benefit CurrentFederalTaxExpenseBenefit	0	usd
CY2020	us-gaap	Current Federal Tax Expense Benefit CurrentFederalTaxExpenseBenefit	0	usd
CY2022	us-gaap	Current State And Local Tax Expense Benefit CurrentStateAndLocalTaxExpenseBenefit	-79000	usd
CY2021	us-gaap	Current State And Local Tax Expense Benefit CurrentStateAndLocalTaxExpenseBenefit	0	usd
CY2020	us-gaap	Current State And Local Tax Expense Benefit CurrentStateAndLocalTaxExpenseBenefit	420000	usd
CY2022	us-gaap	Current Foreign Tax Expense Benefit CurrentForeignTaxExpenseBenefit	173000	usd
CY2021	us-gaap	Current Foreign Tax Expense Benefit CurrentForeignTaxExpenseBenefit	322000	usd
CY2020	us-gaap	Current Foreign Tax Expense Benefit CurrentForeignTaxExpenseBenefit	1050000	usd
CY2022	us-gaap	Deferred Federal Income Tax Expense Benefit DeferredFederalIncomeTaxExpenseBenefit	0	usd
CY2021	us-gaap	Deferred Federal Income Tax Expense Benefit DeferredFederalIncomeTaxExpenseBenefit	-253000	usd
CY2020	us-gaap	Deferred Federal Income Tax Expense Benefit DeferredFederalIncomeTaxExpenseBenefit	-10631000	usd
CY2022	us-gaap	Deferred State And Local Income Tax Expense Benefit DeferredStateAndLocalIncomeTaxExpenseBenefit	0	usd
CY2021	us-gaap	Deferred State And Local Income Tax Expense Benefit DeferredStateAndLocalIncomeTaxExpenseBenefit	0	usd
CY2020	us-gaap	Deferred State And Local Income Tax Expense Benefit DeferredStateAndLocalIncomeTaxExpenseBenefit	-2319000	usd
CY2022	us-gaap	Deferred Foreign Income Tax Expense Benefit DeferredForeignIncomeTaxExpenseBenefit	0	usd
CY2021	us-gaap	Deferred Foreign Income Tax Expense Benefit DeferredForeignIncomeTaxExpenseBenefit	0	usd
CY2020	us-gaap	Deferred Foreign Income Tax Expense Benefit DeferredForeignIncomeTaxExpenseBenefit	0	usd
CY2022	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	94000	usd
CY2021	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	69000	usd
CY2020	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	-11480000	usd
CY2022	us-gaap	Effective Income Tax Rate Reconciliation At Federal Statutory Income Tax Rate EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate	0.21
CY2021	us-gaap	Effective Income Tax Rate Reconciliation At Federal Statutory Income Tax Rate EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate	0.21
CY2020	us-gaap	Effective Income Tax Rate Reconciliation At Federal Statutory Income Tax Rate EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate	0.21
CY2022	us-gaap	Effective Income Tax Rate Reconciliation State And Local Income Taxes EffectiveIncomeTaxRateReconciliationStateAndLocalIncomeTaxes	0
CY2021	us-gaap	Effective Income Tax Rate Reconciliation State And Local Income Taxes EffectiveIncomeTaxRateReconciliationStateAndLocalIncomeTaxes	0
CY2020	us-gaap	Effective Income Tax Rate Reconciliation State And Local Income Taxes EffectiveIncomeTaxRateReconciliationStateAndLocalIncomeTaxes	0.02
CY2022	us-gaap	Effective Income Tax Rate Reconciliation Change In Deferred Tax Assets Valuation Allowance EffectiveIncomeTaxRateReconciliationChangeInDeferredTaxAssetsValuationAllowance	-0.14
CY2021	us-gaap	Effective Income Tax Rate Reconciliation Change In Deferred Tax Assets Valuation Allowance EffectiveIncomeTaxRateReconciliationChangeInDeferredTaxAssetsValuationAllowance	-0.30
CY2020	us-gaap	Effective Income Tax Rate Reconciliation Change In Deferred Tax Assets Valuation Allowance EffectiveIncomeTaxRateReconciliationChangeInDeferredTaxAssetsValuationAllowance	-0.35
CY2022	us-gaap	Effective Income Tax Rate Reconciliation Foreign Income Tax Rate Differential EffectiveIncomeTaxRateReconciliationForeignIncomeTaxRateDifferential	0
CY2021	us-gaap	Effective Income Tax Rate Reconciliation Foreign Income Tax Rate Differential EffectiveIncomeTaxRateReconciliationForeignIncomeTaxRateDifferential	0
CY2020	us-gaap	Effective Income Tax Rate Reconciliation Foreign Income Tax Rate Differential EffectiveIncomeTaxRateReconciliationForeignIncomeTaxRateDifferential	-0.05
CY2022	fsly	Effective Income Tax Rate Reconciliation Acquisition Related Expenses Percent EffectiveIncomeTaxRateReconciliationAcquisitionRelatedExpensesPercent	0
CY2021	fsly	Effective Income Tax Rate Reconciliation Acquisition Related Expenses Percent EffectiveIncomeTaxRateReconciliationAcquisitionRelatedExpensesPercent	0
CY2020	fsly	Effective Income Tax Rate Reconciliation Acquisition Related Expenses Percent EffectiveIncomeTaxRateReconciliationAcquisitionRelatedExpensesPercent	-0.02
CY2022	us-gaap	Effective Income Tax Rate Reconciliation Nondeductible Expense Share Based Compensation Cost EffectiveIncomeTaxRateReconciliationNondeductibleExpenseShareBasedCompensationCost	-0.09
CY2021	us-gaap	Effective Income Tax Rate Reconciliation Nondeductible Expense Share Based Compensation Cost EffectiveIncomeTaxRateReconciliationNondeductibleExpenseShareBasedCompensationCost	0.02
CY2020	us-gaap	Effective Income Tax Rate Reconciliation Nondeductible Expense Share Based Compensation Cost EffectiveIncomeTaxRateReconciliationNondeductibleExpenseShareBasedCompensationCost	0.30
CY2022	us-gaap	Effective Income Tax Rate Reconciliation Nondeductible Expense Research And Development EffectiveIncomeTaxRateReconciliationNondeductibleExpenseResearchAndDevelopment	0.02
CY2021	us-gaap	Effective Income Tax Rate Reconciliation Nondeductible Expense Research And Development EffectiveIncomeTaxRateReconciliationNondeductibleExpenseResearchAndDevelopment	0.05
CY2020	us-gaap	Effective Income Tax Rate Reconciliation Nondeductible Expense Research And Development EffectiveIncomeTaxRateReconciliationNondeductibleExpenseResearchAndDevelopment	0
CY2022	us-gaap	Effective Income Tax Rate Reconciliation Nondeductible Expense Restructuring Charges EffectiveIncomeTaxRateReconciliationNondeductibleExpenseRestructuringCharges	0
CY2021	us-gaap	Effective Income Tax Rate Reconciliation Nondeductible Expense Restructuring Charges EffectiveIncomeTaxRateReconciliationNondeductibleExpenseRestructuringCharges	0.02
CY2020	us-gaap	Effective Income Tax Rate Reconciliation Nondeductible Expense Restructuring Charges EffectiveIncomeTaxRateReconciliationNondeductibleExpenseRestructuringCharges	0
CY2022	us-gaap	Effective Income Tax Rate Continuing Operations EffectiveIncomeTaxRateContinuingOperations	0
CY2021	us-gaap	Effective Income Tax Rate Continuing Operations EffectiveIncomeTaxRateContinuingOperations	0
CY2020	us-gaap	Effective Income Tax Rate Continuing Operations EffectiveIncomeTaxRateContinuingOperations	0.11
CY2022	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	100000	usd
CY2021	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	100000	usd
CY2020	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	-11500000	usd
CY2022Q4	us-gaap	Deferred Tax Assets Operating Loss Carryforwards DeferredTaxAssetsOperatingLossCarryforwards	183306000	usd
CY2021Q4	us-gaap	Deferred Tax Assets Operating Loss Carryforwards DeferredTaxAssetsOperatingLossCarryforwards	162260000	usd
CY2022Q4	fsly	Deferred Tax Asset Lease Liability DeferredTaxAssetLeaseLiability	23245000	usd
CY2021Q4	fsly	Deferred Tax Asset Lease Liability DeferredTaxAssetLeaseLiability	20415000	usd
CY2022Q4	us-gaap	Deferred Tax Assets In Process Research And Development DeferredTaxAssetsInProcessResearchAndDevelopment	21383000	usd
CY2021Q4	us-gaap	Deferred Tax Assets In Process Research And Development DeferredTaxAssetsInProcessResearchAndDevelopment	16636000	usd
CY2022Q4	fsly	Deferred Tax Assets Capitalized Research And Development Costs DeferredTaxAssetsCapitalizedResearchAndDevelopmentCosts	21032000	usd
CY2021Q4	fsly	Deferred Tax Assets Capitalized Research And Development Costs DeferredTaxAssetsCapitalizedResearchAndDevelopmentCosts	4558000	usd
CY2022Q4	us-gaap	Deferred Tax Assets Tax Deferred Expense Compensation And Benefits Share Based Compensation Cost DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefitsShareBasedCompensationCost	10429000	usd
CY2021Q4	us-gaap	Deferred Tax Assets Tax Deferred Expense Compensation And Benefits Share Based Compensation Cost DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefitsShareBasedCompensationCost	6000000	usd
CY2022Q4	us-gaap	Deferred Tax Assets Deferred Income DeferredTaxAssetsDeferredIncome	2811000	usd
CY2021Q4	us-gaap	Deferred Tax Assets Deferred Income DeferredTaxAssetsDeferredIncome	7821000	usd
CY2022Q4	us-gaap	Deferred Tax Assets Tax Deferred Expense Reserves And Accruals DeferredTaxAssetsTaxDeferredExpenseReservesAndAccruals	4648000	usd
CY2021Q4	us-gaap	Deferred Tax Assets Tax Deferred Expense Reserves And Accruals DeferredTaxAssetsTaxDeferredExpenseReservesAndAccruals	3149000	usd
CY2022Q4	us-gaap	Deferred Tax Assets Other DeferredTaxAssetsOther	4179000	usd
CY2021Q4	us-gaap	Deferred Tax Assets Other DeferredTaxAssetsOther	2761000	usd
CY2022Q4	us-gaap	Deferred Tax Assets Gross DeferredTaxAssetsGross	271033000	usd
CY2021Q4	us-gaap	Deferred Tax Assets Gross DeferredTaxAssetsGross	223600000	usd
CY2022Q4	us-gaap	Deferred Tax Liabilities Goodwill And Intangible Assets DeferredTaxLiabilitiesGoodwillAndIntangibleAssets	21713000	usd
CY2021Q4	us-gaap	Deferred Tax Liabilities Goodwill And Intangible Assets DeferredTaxLiabilitiesGoodwillAndIntangibleAssets	26493000	usd
CY2022Q4	us-gaap	Deferred Tax Liabilities Leasing Arrangements DeferredTaxLiabilitiesLeasingArrangements	18847000	usd
CY2021Q4	us-gaap	Deferred Tax Liabilities Leasing Arrangements DeferredTaxLiabilitiesLeasingArrangements	19073000	usd
CY2022Q4	fsly	Deferred Tax Liabilities State Taxes DeferredTaxLiabilitiesStateTaxes	10732000	usd
CY2021Q4	fsly	Deferred Tax Liabilities State Taxes DeferredTaxLiabilitiesStateTaxes	8969000	usd
CY2022Q4	us-gaap	Deferred Tax Liabilities Prepaid Expenses DeferredTaxLiabilitiesPrepaidExpenses	11526000	usd
CY2021Q4	us-gaap	Deferred Tax Liabilities Prepaid Expenses DeferredTaxLiabilitiesPrepaidExpenses	5073000	usd
CY2022Q4	us-gaap	Deferred Income Tax Liabilities DeferredIncomeTaxLiabilities	62818000	usd
CY2021Q4	us-gaap	Deferred Income Tax Liabilities DeferredIncomeTaxLiabilities	59608000	usd
CY2022Q4	us-gaap	Deferred Tax Assets Valuation Allowance DeferredTaxAssetsValuationAllowance	208215000	usd
CY2021Q4	us-gaap	Deferred Tax Assets Valuation Allowance DeferredTaxAssetsValuationAllowance	163992000	usd
CY2022Q4	us-gaap	Deferred Tax Liabilities DeferredTaxLiabilities	0	usd
CY2021Q4	us-gaap	Deferred Tax Liabilities DeferredTaxLiabilities	0	usd
CY2022	us-gaap	Valuation Allowance Deferred Tax Asset Change In Amount ValuationAllowanceDeferredTaxAssetChangeInAmount	44200000	usd
CY2021Q4	us-gaap	Unrecognized Tax Benefits UnrecognizedTaxBenefits	7808000	usd
CY2020Q4	us-gaap	Unrecognized Tax Benefits UnrecognizedTaxBenefits	3186000	usd
CY2022	us-gaap	Unrecognized Tax Benefits Increases Resulting From Prior Period Tax Positions UnrecognizedTaxBenefitsIncreasesResultingFromPriorPeriodTaxPositions	8697000	usd
CY2021	us-gaap	Unrecognized Tax Benefits Increases Resulting From Prior Period Tax Positions UnrecognizedTaxBenefitsIncreasesResultingFromPriorPeriodTaxPositions	3113000	usd
CY2022	us-gaap	Unrecognized Tax Benefits Decreases Resulting From Prior Period Tax Positions UnrecognizedTaxBenefitsDecreasesResultingFromPriorPeriodTaxPositions	751000	usd
CY2021	us-gaap	Unrecognized Tax Benefits Decreases Resulting From Prior Period Tax Positions UnrecognizedTaxBenefitsDecreasesResultingFromPriorPeriodTaxPositions	31000	usd
CY2022	us-gaap	Unrecognized Tax Benefits Increases Resulting From Current Period Tax Positions UnrecognizedTaxBenefitsIncreasesResultingFromCurrentPeriodTaxPositions	1583000	usd
CY2021	us-gaap	Unrecognized Tax Benefits Increases Resulting From Current Period Tax Positions UnrecognizedTaxBenefitsIncreasesResultingFromCurrentPeriodTaxPositions	1540000	usd
CY2022Q4	us-gaap	Unrecognized Tax Benefits UnrecognizedTaxBenefits	17337000	usd
CY2021Q4	us-gaap	Unrecognized Tax Benefits UnrecognizedTaxBenefits	7808000	usd
CY2022Q4	us-gaap	Unrecognized Tax Benefits That Would Impact Effective Tax Rate UnrecognizedTaxBenefitsThatWouldImpactEffectiveTaxRate	17300000	usd
CY2021Q4	us-gaap	Unrecognized Tax Benefits That Would Impact Effective Tax Rate UnrecognizedTaxBenefitsThatWouldImpactEffectiveTaxRate	7800000	usd
CY2022Q4	fsly	Property Plant And Equipment Net And Operating Lease Right Of Use Assets Net PropertyPlantAndEquipmentNetAndOperatingLeaseRightOfUseAssetsNet	248818000	usd
CY2021Q4	fsly	Property Plant And Equipment Net And Operating Lease Right Of Use Assets Net PropertyPlantAndEquipmentNetAndOperatingLeaseRightOfUseAssetsNet	236592000	usd
CY2022	dei	Auditor Name AuditorName	Deloitte & Touche LLP

Files In Submission

Name	View Source	Status
0001517413-23-000035-index-headers.html	Edgar Link	pending
0001517413-23-000035-index.html	Edgar Link	pending
0001517413-23-000035.txt	Edgar Link	pending
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report.css	Edgar Link	pending
Show.js	Edgar Link	pending
fsly-20221231_cal.xml	Edgar Link	unprocessable

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$FSLY
Fastly, Inc. Stock $fsly

2023 Q1 Form 10-K Financial Statement

#000151741323000035 Filed on February 27, 2023

Income Statement

Balance Sheet

Cashflow Statement

Facts In Submission

Files In Submission

$FSLY Fastly, Inc. Stock $fsly

2023 Q1 Form 10-K Financial Statement

#000151741323000035 Filed on February 27, 2023

Income Statement

Balance Sheet

Cashflow Statement

Facts In Submission

Files In Submission

$FSLY
Fastly, Inc. Stock $fsly