Stock-Based Compensation and Employee Benefit Plan - Stock Option and Restricted Stock Activity (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended	9 Months Ended	12 Months Ended
	Sep. 30, 2020	Sep. 30, 2020	Dec. 31, 2019
Outstanding Options/RSUs, Number of Shares
Outstanding (in shares)		17,837,316
Granted (in shares)		200,000
Exercised (in shares)		(443,929)
Cancelled (in shares)		(988,360)
Outstanding (in shares)	16,605,027	16,605,027	17,837,316
Outstanding Options Weighted Average Exercise Price
Outstanding (in dollars per share)		$ 20.76
Granted (in dollars per share)	$ 7.30	7.30
Exercised (in dollars per share)		9.56
Cancelled (in dollars per share)		23.01
Outstanding (in dollars per share)	$ 20.76	$ 20.76	$ 20.76
Outstanding, remaining contractual life		6 years 2 months 26 days	6 years 11 months 8 days
Outstanding, aggregate intrinsic value	$ 66,358	$ 66,358	$ 14,964
Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract]
Vested and expected to vest (in shares)	16,188,459	16,188,459
Exercisable (in shares)	10,047,183	10,047,183
Vested and expected to vest, weighted average exercise price (in dollars per share)	$ 21.08	$ 21.08
Exercisable, weighted average exercise price (in dollars per share)	$ 27.82	$ 27.82
Vested and expected to vest, remaining contractual life		6 years 2 months 4 days
Exercisable, remaining contractual life		4 years 8 months 15 days
Vested and expected to vest, aggregate intrinsic value	$ 62,085	$ 62,085
Exercisable, aggregate intrinsic value	$ 5,338	$ 5,338