Condensed Statements of Stockholders' Equity - USD ($) $ in Thousands	Total	Common Stock [Member]	Additional Paid-In Capital [Member]	Accumulated Deficit [Member]	Accumulated Other Comprehensive Income (Loss) [Member]
Balance, Value at Dec. 31, 2014	$ 51,662	$ 23	$ 131,840	$ (80,201)
Balance, Shares at Dec. 31, 2014		22,802,039
Stock-based compensation expense	1,146		1,146
Shares issued upon exercise of stock options, Value	35		35
Shares issued upon exercise of stock options, Shares		34,880
Net loss	(10,373)			(10,373)
Balance, Value at Jun. 30, 2015	42,470	$ 23	133,021	(90,574)
Balance, Shares at Jun. 30, 2015		22,836,919
Balance, Value at Dec. 31, 2015	105,044	$ 27	209,943	(104,891)	$ (35)
Balance, Shares at Dec. 31, 2015		27,254,863
Stock-based compensation expense	1,194		1,194
Shares issued upon exercise of stock options, Value	40		40
Shares issued upon exercise of stock options, Shares		28,000
Net loss	(23,766)			(23,766)
Other comprehensive income	76				76
Balance, Value at Jun. 30, 2016	$ 82,588	$ 27	$ 211,177	$ (128,657)	$ 41
Balance, Shares at Jun. 30, 2016		27,282,863