CONDENSED BALANCE SHEETS - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Current assets:
Cash and cash equivalents	$ 63,941	$ 80,667
Short-term investments	1,400	28,347
Prepaid expenses and other current assets	3,669	2,030
Total current assets	69,010	111,044
Property and equipment, net	1,412	1,853
Restricted cash and other assets	327	334
Total assets	70,749	113,231
Current liabilities:
Accounts payable	849	556
Accrued expenses	6,119	7,394
Current portion of note payable	285	292
Current portion of deferred revenue	563	1,111
Total current liabilities	7,816	9,353
Deferred revenue, net of current portion	94	152
Note payable, net of current portion		209
Other liabilities	759	168
Total liabilities	8,669	9,882
Commitments and contingencies
Stockholders' equity:
Common stock, $0.001 par value, Authorized — 280,000 shares; Issued and outstanding — 149,606 and 149,065 shares at September 30, 2017 and December 31, 2016, respectively	150	149
Additional paid-in capital	651,498	641,687
Accumulated deficit	(589,568)	(538,470)
Accumulated other comprehensive loss		(17)
Total stockholders' equity	62,080	103,349
Total liabilities and stockholders' equity	70,749	113,231
Series A Preferred Stock
Stockholders' equity:
Preferred stock, $0.01 par value, Authorized — 5,000 shares: Series A convertible preferred stock; Designated — 1,500 shares, Issued and outstanding — 1 share