BALANCE SHEETS - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Current assets:
Cash and cash equivalents	$ 22,576	$ 26,178
Short-term investments	2,184	3,922
Prepaid expenses and other current assets	916	199
Total current assets	25,676	30,299
Property and equipment, net	1,148	1,148
Total assets	26,824	31,447
Current liabilities:
Current portion of notes payable	3,500	3,500
Accounts payable	2,236	2,809
Accrued expenses	833	1,775
Total current liabilities	6,569	8,084
Notes payable	870	1,743
Other long-term liabilities	137	141
Total liabilities	7,576	9,968
Stockholders' equity:
Preferred stock, $0.001 par value; 25,000,000 shares authorized, no shares issued and outstanding
Common stock, $0.001 par value; 100,000,000 shares authorized, 21,953,963 issued and 21,924,732 outstanding at March 31, 2017 and 19,734,351 issued and 19,705,120 outstanding at December 31, 2016	22	20
Additional paid-in capital	150,493	147,288
Treasury stock at cost, 29,231 shares at March 31, 2017 and December 31, 2016
Accumulated deficit	(131,267)	(125,829)
Total stockholders’ equity	19,248	21,479
Total liabilities and stockholders’ equity	$ 26,824	$ 31,447