Net Income (Loss) per Common Share (Basic and Diluted Income (Loss) Per Share) (Details) - USD ($)	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014	Dec. 31, 2014
Basic and diluted net income (loss) per common share calculation:
Net income	$ 5,439,000	$ 21,207,000	$ 1,715,000	$ 23,773,000	$ 23,109,000
Accretion of redeemable convertible preferred stock	(7,163,000)	(323,000)	(9,329,000)	(955,000)
Net (loss) income attributable to common stockholders	$ (1,724,000)	$ 20,884,000	$ (7,614,000)	$ 22,818,000
Weighted average number of shares of common stock outstanding - basic	5,813,063	3,743,182	5,247,508	3,688,903
Net (loss) income per share of common stock - basic	$ (0.30)	$ 5.58	$ (1.45)	$ 6.19
Weighted average number of shares of common stock outstanding - diluted	5,813,063	6,319,802	5,247,508	6,472,093
Net (loss) income per share of common stock - diluted	$ (0.30)	$ 3.30	$ (1.45)	$ 3.53