Stockholders' Equity - Summary of Option Activity (Details) - $ / shares	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Number of Options
Outstanding at beginning of period (in options)	459,271	286,188	218,458
Granted (in options)	340,500	326,250	207,950
Canceled (in options)	(147,152)	(145,873)	(138,220)
Exercised (in options)	(50,412)	(7,294)	(2,000)
Outstanding at end of period (in options)	602,207	459,271	286,188
Vested and expected to vest (in options)	565,137
Exercisable (in options)	304,610
Weighted Average Exercise Price Per Share
Outstanding at beginning of period (in dollars per share)	$ 8.95	$ 15.30	$ 22.00
Granted (in dollars per share)	8.65	4.76	3.15
Canceled (in dollars per share)	10.10	12.38	7.74
Exercised (in dollars per share)	4.69	2.30	5.15
Outstanding at end of period (in dollars per share)	8.58	$ 8.95	$ 15.30
Vested and expected to vest (in dollars per share)	8.71
Exercisable (in dollars per share)	$ 9.38