BALANCE SHEETS (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Statement of Financial Position [Abstract]
Allowance for doubtful accounts	$ 5	$ 5
Preferred stock, par value	$ 0.01	$ .01
Preferred stock, shares authorized	24,088	24,088
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, par value	$ 0.01	$ .01
Common stock, shares authorized	42,000,000	42,000,000
Common stock, shares issued	33,847,793	31,229,996
Common stock, shares outstanding	33,847,793	31,229,996