Stock-Based Compensation and Employee Benefit Plan - Stock Option and Restricted Stock Activity (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Outstanding Options/RSUs, Number of Shares
Outstanding (in shares)	17,837,316	14,558,420
Granted (in shares)	200,000	4,956,064
Exercised (in shares)	(1,341,324)	(358,564)
Cancelled (in shares)	(1,341,721)	(1,318,604)
Outstanding (in shares)	15,354,271	17,837,316	14,558,420
Outstanding Options Weighted Average Exercise Price
Outstanding (in dollars per share)	$ 20.76	$ 25.93
Granted (in dollars per share)	7.30	5.60
Exercised (in dollars per share)	11.18	4.26
Cancelled (in dollars per share)	22.49	25.33
Outstanding (in dollars per share)	$ 21.27	$ 20.76	$ 25.93
Outstanding, remaining contractual life	6 years	6 years 10 months 24 days	6 years 9 months 18 days
Outstanding, aggregate intrinsic value	$ 129,855	$ 14,964	$ 3,084
Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract]
Vested and expected to vest (in shares)	14,976,706
Exercisable (in shares)	10,311,316
Vested and expected to vest, weighted average exercise price (in dollars per share)	$ 21.55
Exercisable, weighted average exercise price (in dollars per share)	$ 26.37
Vested and expected to vest, remaining contractual life	5 years 10 months 24 days
Exercisable, remaining contractual life	4 years 10 months 24 days
Vested and expected to vest, aggregate intrinsic value	$ 122,813
Exercisable, aggregate intrinsic value	$ 39,569