Stock-Based Compensation - Summary of RSUs (Details) - RSUs - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Number of Stock RSUs Outstanding
Shares, beginning balance	1,617,551	884,101	254,863
Shares, granted	40,000	1,485,488	847,750
Shares, vested	(917,926)	(285,270)	(74,985)
Shares, forfeited	(375,783)	(466,768)	(143,527)
Shares, ending balance	363,842	1,617,551	884,101
Shares, vested and expected to vest as of December 31, 2015	265,932
Weighted-Average Grant Date Fair Value
Weighted average grant-date fair value, beginning balance	$ 3.79	$ 7.69	$ 6.45
Weighted average grant-date fair value, granted	1.66	2.75	8.13
Weighted average grant-date fair value, forfeited	4.55	5.83	8.56
Weighted average grant-date fair value, ending balance	$ 4.72	$ 3.79	$ 7.69
Additional information
Value of restricted stock granted during period		$ 1.0
Vesting period	4 years	1 year
Aggregate intrinsic value of RSUs outstanding	$ 0.8	$ 3.1
Fair value of vested awarded stock	$ 2.8	$ 2.0