Condensed Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Current assets:
Cash and cash equivalents	$ 5,117	$ 8,496
Restricted cash	50	50
Short-term investments	5,500
Prepaid expenses	311	442
Total current assets	10,978	8,988
Property and equipment, net of accumulated depreciation of $778 and $702, in 2015 and 2014, respectively	163	183
Other assets	18	18
Total assets	11,159	9,189
Current liabilities:
Accounts payable	1,163	285
Accrued expenses	1,106	1,002
Deferred revenue		47
Total current liabilities	$ 2,269	$ 1,334
Commitments and contingencies (Note 6)
Stockholders' equity:
Preferred stock	$ 0	$ 0
Common stock, $0.0001 par value, 100,000,000 shares authorized; 65,349,121 and 21,984,272 shares issued and outstanding at December 31, 2015 and 2014, respectively	7	2
Additional paid-in capital	65,988	48,047
Accumulated deficit	(57,105)	(46,882)
Total stockholders' equity	8,890	2,745
Total liabilities, convertible preferred stock and stockholders' equity	$ 11,159	9,189
Series A Convertible Preferred Stock [Member]
Convertible preferred stock:
Series A convertible preferred stock, $0.0001 par value, no shares authorized, issued or outstanding at December 31, 2015; 15,000 shares authorized and 5,110 shares issued and outstanding at December 31, 2014 (at liquidation value)		5,110
Series A-1 Convertible Preferred Stock [Member]
Stockholders' equity:
Preferred stock		1,578
Total stockholders' equity		$ 1,578