Share-Based Compensation - Share-Based Payment Award Activity (Details) - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Outstanding, Beginning Balance (shares)	463,913	407,950	349,454
Granted (shares)	245,539	255,914	198,647
Exercised (shares)	(15,415)	(16,878)	(6,812)
Forfeited (shares)	(94,064)	(183,073)	(133,339)
Outstanding, Ending Balance (shares)	599,973	463,913	407,950	349,454
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Roll Forward]
Outstanding, Beginning Balance, weighted average exercise price (usd per share)	$ 15.10	$ 22.12	$ 28.15
Granted, weighted average exercise price (usd per share)	10.93	10.46	14.11
Exercised, weighted average exercise price (usd per share)	9.42	11.27	10.55
Forfeited, weighted average exercise price (usd per share)	20.77	23.84	26.58
Outstanding, Ending Balance, weighted average exercise price (usd per share)	$ 12.68	$ 15.10	$ 22.12	$ 28.15
Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract]
Outstanding, weighted average remaining contractual term	8 years 18 days	7 years 11 months 16 days	4 years 10 months 21 days	4 years 4 months 2 days
Outstanding, aggregate intrinsic value	$ 0	$ 614,591	$ 22,479	$ 48,939
Vested and expected to vest (shares)	544,232
Vested and expected to vest, weighted average exercise price (usd per share)	$ 12.86
Vested and expected to vest, weighted average remaining contractual term	7 years 11 months 9 days
Vested and expected to vest, aggregate intrinsic value	$ 0
Exercisable (shares)	219,956
Exercisable, weighted average exercise price (usd per share)	$ 15.57
Exercisable, weighted average remaining contractual term	6 years 5 months 23 days
Exercisable, aggregate intrinsic value, per share	$ 0
Total intrinsic value of stock options exercised	34,000	42,000	17,000
Cash received from stock options exercised	145,000	190,000	72,000
Total value of restricted shares vested	$ 697,000	$ 380,000	$ 525,000