Condensed Statements of Operations (Unaudited) (Parenthetical) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Research and Development Expense [Member]
Non-cash stock-based compensation expenses	$ 203	$ 206	$ 378	$ 416
General and Administrative Expense [Member]
Non-cash stock-based compensation expenses	$ 244	$ 251	$ 480	$ 532