Fair Value Measurements - Narrative (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended	12 Months Ended
	Sep. 30, 2021	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Mar. 26, 2021	Dec. 31, 2015	Dec. 31, 2014
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Number of shares called by warrants (in shares)						66,668	241,964
Exercise price of shares called by warrants (in dollars per share)						$ 1.50	$ 2.0663
Warrants, term		10 years
Shares of common stock reserved for future issuance (in shares)		33,130,000	80,602,519
Gain on remeasurement of warrants	$ 556	$ 556	$ (12,825)	$ (411)
IPO
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Sale of stock, price per share (in dollars per share)					$ 47.00
Redeemable convertible preferred stock warrants
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Shares of common stock reserved for future issuance (in shares)			308,632