Stock-Based Compensation - Schedule of Activity under 2008 Plan and 2018 Plan (Details) $ / shares in Units, shares in Thousands, $ in Thousands	6 Months Ended	12 Months Ended
	Jun. 30, 2023 USD ($) $ / shares shares	Dec. 31, 2022 USD ($) $ / shares shares
Number of Options (In Thousands)
Beginning balance (in shares) | shares	14,215
Options granted (in shares) | shares	5,029
Options exercised (in shares) | shares	(351)
Options forfeited (in shares) | shares	(2,494)
Options expired (in shares) | shares	(375)
Ending balance (in shares) | shares	16,024	14,215
Vested and expected to vest (in shares) | shares	15,556
Exercisable (in shares) | shares	9,303
Weighted Average Exercise Price
Beginning balance (in dollars per share) | $ / shares	$ 14.74
Options granted (in dollars per share) | $ / shares	4.32
Options exercised (in dollars per share) | $ / shares	1.90
Options forfeited (in dollars per share) | $ / shares	11.42
Options expired (in dollars per shares) | $ / shares	14.80
Ending balance (in dollars per share) | $ / shares	12.27	$ 14.74
Vested and expected to vest, weighted average exercise price (in dollars per share) | $ / shares	12.35
Exercisable, weighted average exercise price (in dollars per share) | $ / shares	$ 14.51
Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract]
Weighted Average Remaining Contractual Life (In Years)	6 years 2 months 26 days	6 years 10 months 20 days
Vested and expected to vest, weighted average remaining contractual life	6 years 1 month 28 days
Exercisable, weighted average remaining contractual life	4 years 1 month 20 days
Aggregate intrinsic value | $	$ 40	$ 1,749
Vested and expected to vest, aggregate intrinsic value | $	40
Exercisable, aggregate intrinsic value | $	$ 40