Stockholders' Equity - Summary of the share activity under the 2015 Plan (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2022	Dec. 31, 2021
Stock option
Aggregate Intrinsic Value
Unrecognized compensation costs	$ 2,100
Weighted-average remaining requisite service period	1 year 3 months 18 days
2015 Equity Incentive Plan
Number of shares
Outstanding at the beginning	4,560
Granted	714
Exercised	(308)
Forfeited	(250)
Expired	(512)
Outstanding at the end	4,204	4,560
Expected to vest	4,204
Exercisable	3,315
Weighted Average Exercise Price
Outstanding at the beginning (in dollars per share)	$ 6.29
Granted (in dollars per share)	3.88
Exercised (in dollars per share)	1.02
Forfeited (in dollars per share)	6.33
Expired (in dollars per share)	7.48
Outstanding at the end (in dollars per share)	6.12	$ 6.29
Expected to vest (in dollars per share)	6.12
Exercisable (in dollars per share)	$ 6.23
Weighted Average Remaining Contractual Term
Weighted Average Remaining Term (in years)	3 years 6 months 29 days	3 years 25 days
Vested and expected to vest (in years)	3 years 6 months 21 days
Exercisable (in years)	2 years 1 month 2 days
Aggregate Intrinsic Value
Outstanding	$ 178	$ 2,670
Expected to vest	178
Exercisable	$ 178