Stockholders' Equity - Summary of the Share Activity Under the 2015 Plan (Details) - 2015 Equity Incentive Plan - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended	6 Months Ended
	Mar. 31, 2023	Jun. 30, 2023	Dec. 31, 2022
Number of Shares
Outstanding at the beginning (in shares)	3,976	3,976
Granted (in shares)		51
Exercised (in shares)		(34)
Forfeited (in shares)		(132)
Expired (in shares)		(143)
Outstanding at the end (in shares)		3,718
Expected to vest (in shares)		3,718
Exercisable (in shares)		3,235
Weighted Average Exercise Price
Outstanding at the beginning (in dollars per share)	$ 6.20	$ 6.20
Granted (in dollars per share)		0.61
Exercised (in dollars per share)		0.86
Forfeited (in dollars per share)		5.18
Expired (in dollars per share)		5.05
Outstanding at the end (in dollars per share)		6.25
Expected to vest (in dollars per share)		6.25
Exercisable (in dollars per share)		$ 6.46
Weighted Average Remaining Term
Weighted Average Remaining Term (in years)	3 years 9 months 18 days	3 years 1 month 9 days
Vested and expected to vest (in years)		3 years 1 month 9 days
Exercisable (in years)		2 years 3 months 10 days
Aggregate Intrinsic Value
Outstanding		$ 0	$ 0
Expected to vest		0
Exercisable		$ 0