Share-Based Compensation - Stock Options (Details) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2020 USD ($) $ / shares shares
Stock Options, Outstanding [Roll Forward]
Stock options outstanding, beginning balance (in shares) | shares	5,121
Granted (in shares) | shares	2,551
Exercised (in shares) | shares	(403)
Forfeited (in shares) | shares	(566)
Expired (in shares) | shares	(805)
Stock options outstanding, ending balance (in shares) | shares	5,898
Stock options exercisable (in shares) | shares	2,172
Stock Options, Outstanding, Weighted Average Exercise Price [Abstract]
Stock options outstanding, beginning balance (in usd per share) | $ / shares	$ 7.51
Granted (in usd per share) | $ / shares	6.90
Exercised (in usd per share) | $ / shares	5.08
Forfeited (in usd per share) | $ / shares	3.24
Expired (in usd per share) | $ / shares	13.37
Stock options outstanding, ending balance (in usd per share) | $ / shares	7.02
Stock options exercisable (in usd per share) | $ / shares	$ 9.48
Stock options outstanding, Weighted Average Remaining Contractual Life (in years)	7 years 11 months 15 days
Stock options exercisable, Weighted Average Remaining Contractual Life (in years)	5 years 6 months 29 days
Stock options outstanding, Aggregate Intrinsic Value | $	$ 7,115
Stock options exercisable, Aggregate Intrinsic Value | $	$ 1,841