Debt - Additional Information (Details) - USD ($)				1 Months Ended								3 Months Ended	7 Months Ended	12 Months Ended		13 Months Ended
	Apr. 26, 2021	Jun. 30, 2020	Mar. 31, 2020	Apr. 30, 2021	Sep. 30, 2020	Aug. 31, 2020	Mar. 31, 2020	Jan. 31, 2020	Sep. 30, 2019	Mar. 31, 2019	Nov. 30, 2014	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2021	Dec. 31, 2020	Apr. 30, 2021	Sep. 24, 2020	Jul. 01, 2020	Apr. 30, 2020	Dec. 31, 2019
Debt Instrument [Line Items]
Payment of debt issuance costs														$ 0	$ 950,000
Redeemable convertible preferred stock warrant liability														0	369,000
PIK interest paid on repayment of term loan														0	(4,081,000)
Repayments of debt														4,090,000	42,120,000
Proceeds from convertible debt														0	12,535,000
Proceeds from related party debt														0	11,867,000
Interest expense, related party														0	1,258,000
Gain (loss) on extinguishment of debt														$ 0	(182,000)
Redeemable Convertible Preferred Stock Converted Into Warrants To Purchase Common Stock
Debt Instrument [Line Items]
Conversion of stock, shares issued (in shares)	219
Convertible Debt
Debt Instrument [Line Items]
Interest rate			8.00%				8.00%		8.00%				8.00%
Interest payment															1,400,000
Interest expense															4,600,000
Equity financing proceed threshold for conversion					$ 18,000,000							$ 18,000,000
Threshold percentage of stock price trigger					85.00%
Conversion price (in dollars per share)						$ 4,342,300
Amortization of debt discount															3,200,000
Proceeds from related party debt															10,300,000
Interest expense, related party															$ 1,300,000
Convertible Debt | Conversion of Series B’ redeemable convertible preferred stock
Debt Instrument [Line Items]
Conversion discount						15.00%
Convertible debt outstanding						$ 33,900,000
Interest payable						$ 2,500,000
Converted instrument, shares issued (in shares)						8,379,410
Share issuance price percentage						100.00%
Gain (loss) on extinguishment of debt												$ 4,100,000
Convertible Debt | Conversion of Series A’ redeemable convertible preferred stock
Debt Instrument [Line Items]
Conversion price (in dollars per share)					$ 116.35							$ 116.35
Repayment premium percent					100.00%							100.00%
Minimum | Convertible Debt
Debt Instrument [Line Items]
Effective percentage															10.80%
Maximum | Convertible Debt
Debt Instrument [Line Items]
Effective percentage															12.20%
2014 Term Loan
Debt Instrument [Line Items]
Face amount											$ 40,000,000									$ 40,000,000
Interest rate											12.50%
Redemption fee, percent											5.00%
Payment of debt issuance costs											$ 800,000
Effective percentage								14.70%										14.20%
Interest payment			$ 1,400,000		$ 1,300,000
PIK interest paid on repayment of term loan		$ 1,400,000
Repayments of debt					47,600,000
Repurchased face amount					44,100,000							$ 44,100,000
Payment for debt extinguishment					2,200,000
2014 Term Loan | Series I Preferred Stock
Debt Instrument [Line Items]
Number of securities called by warrants or rights (in shares)											219
Exercise price of warrant (in dollars per share)											$ 1,866.8
Redeemable convertible preferred stock warrant liability											$ 300,000
2014 Term Loan | Common stock warrants issued and outstanding
Debt Instrument [Line Items]
Number of securities called by warrants or rights (in shares)											219
Exercise price of warrant (in dollars per share)											$ 2.60
2020 Term Loan
Debt Instrument [Line Items]
Face amount					$ 50,000,000							$ 50,000,000
Interest rate					12.50%							12.50%
Redemption fee, percent					10.00%							10.00%
Effective percentage														15.66%
Unused borrowing capacity					$ 10,000,000							$ 10,000,000
Amortization of debt issuance costs														$ 300,000	$ 100,000
Interest expense														$ 7,400,000	$ 2,000,000
2020 Term Loan | Maximum
Debt Instrument [Line Items]
Face amount					60,000,000							60,000,000
2020 Term Loan | Conversion of Series B’ redeemable convertible preferred stock
Debt Instrument [Line Items]
Redeemable convertible preferred stock warrant liability																	$ 600,000
Backend fee					$ 1,000,000							$ 1,000,000
Warrants outstanding (in shares)																	346,823,000
Paycheck Protection Program, CARES Act
Debt Instrument [Line Items]
Face amount																			$ 4,000,000
Interest rate																			1.00%
Interest payment																$ 100,000
Repurchased face amount				$ 4,000,000												$ 4,000,000
Repayment of PPP loan				$ 4,100,000
2019 Convertible Notes | Convertible Debt
Debt Instrument [Line Items]
Proceeds from convertible debt													$ 21,300,000
Amortization of debt discount									$ 1,900,000	$ 4,100,000
2020 Convertible Notes | Convertible Debt
Debt Instrument [Line Items]
Proceeds from convertible debt							$ 5,400,000	$ 7,100,000
Amortization of debt discount							$ 700,000	$ 1,000,000