Consolidated Statements of Shareholders' Equity - USD ($) shares in Thousands, $ in Thousands	Total	Preferred Stock [Member]	Common Stock [Member]	Additional Paid-in Capital [Member]	Accumulated Deficit [Member]
Balance at Dec. 31, 2014	$ 52,174	$ 50	$ 8	$ 60,222	$ (8,106)
Balance, shares at Dec. 31, 2014		10	8,427
Exercise of stock options	1,129		$ 1	1,128
Exercise of stock options, shares			71
Issuance of restricted common stock, shares			119
Forfeiture of restricted common stock, shares			(28)
Purchase and retirement of common stock	(1,035)			(1,035)
Purchase and retirement of common stock, shares			(36)
Stock-based compensation	2,571			2,571
Net loss	(8,162)				(8,162)
Balance at Jun. 30, 2015	46,677	$ 50	$ 9	62,886	(16,268)
Balance, shares at Jun. 30, 2015		10	8,553
Balance at Dec. 31, 2015	51,458	$ 50	$ 9	77,439	(26,040)
Balance, shares at Dec. 31, 2015		10	8,919
Exercise of stock options	$ 309			309
Exercise of stock options, shares	32		32
Issuance of restricted common stock, shares			177
Forfeiture of restricted common stock, shares			(3)
Purchase and retirement of common stock	$ (1,104)			(1,104)
Purchase and retirement of common stock, shares			(40)
Stock-based compensation	2,782			2,782
Net loss	(10,718)				(10,718)
Balance at Jun. 30, 2016	$ 42,727	$ 50	$ 9	$ 79,426	$ (36,758)
Balance, shares at Jun. 30, 2016		10	9,085