BALANCE SHEETS - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015
Current assets:
Cash and cash equivalents	$ 46,729	$ 51,722
Short-term Investments	4,471	4,474
Prepaid expenses and other current assets	516	1,571
Total current assets	51,716	57,767
Property and equipment, net	779	31
Investments	248	1,488
Other assets	43	362
Total assets	52,786	59,648
Current liabilities:
Current portion of notes payable	2,878	2,128
Accounts payable	2,553	3,146
Accrued expenses	2,323	2,161
Total current liabilities	7,754	7,435
Notes payable	4,363	5,236
Other long-term liabilities	102	56
Total liabilities	$ 12,219	$ 12,727
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, 19,538,451 issued and 19,509,220 outstanding at March 31, 2016 and 19,420,086 issued and 19,390,855 outstanding at December 31, 2015	$ 20	$ 19
Additional paid-in capital	144,949	144,088
Accumulated deficit	(104,402)	(97,186)
Total stockholders’ equity	40,567	46,921
Total liabilities and stockholders’ equity	$ 52,786	$ 59,648