Stock-based Awards - Schedule of Restricted Stock Units Activity (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Number of Shares
Non-vested at the end of the period (in dollars per share)	7,536,114
Weighted-Average Grant Date Fair Value
Total stock-based compensation expense	$ 20,395	$ 23,077	$ 36,462
Restricted Stock Units (RSUs)
Stock-based Awards
Fair value of shares of restricted stock awards vested	$ 15,800	$ 11,600	$ 16,000
Number of Shares
Non-vested at the beginning of period (in shares)	6,918,474
Granted (in shares)	6,173,367
Vested (in shares)	(3,397,105)
Canceled/forfeited (in shares)	(2,158,622)
Non-vested at the end of the period (in dollars per share)	7,536,114	6,918,474
Weighted-Average Grant Date Fair Value
Non-vested at the beginning of period (in dollars per share)	$ 4.63
Granted (in dollars per share)	4.64	$ 3.08	$ 6.36
Vested (in dollars per share)	4.74
Canceled/forfeited (in dollars per share)	4.57
Non-vested at the end of the period (in dollars per share)	$ 4.60	$ 4.63
Total stock-based compensation expense	$ 16,700	$ 17,600	$ 23,200