Stock-Based Compensation - Summary of Information Related to Stock Options (Details) - Stock Options - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Options
Outstanding at the beginning of the period (in shares)	3,265,900
Granted (in shares)	1,237,455
Exercised (in shares)	(45,932)
Lapsed (forfeited or cancelled) (in shares)	(13,030)
Outstanding at the end of the period (in shares)	4,444,393
Exercisable at the end of the period (in shares)	2,334,518
Weighted Average Exercise Price
Outstanding at the beginning of the period (in dollars per share)	$ 15.45
Granted (in dollars per share)	12.72
Exercised (in dollars per share)	8.23
Lapsed (forfeited or cancelled) (in dollars per share)	31.51
Outstanding at the end of the period (in dollars per share)	14.72
Exercisable at the end of the period (in dollars per share)	$ 10.05
Weighted Average Remaining Life (Years)
Outstanding at the end of the period	5 years 3 months 18 days
Intrinsic Value
Exercisable at the end of the period	$ 12,784
Additional information
Cash proceeds from exercises of options	$ 200	$ 500