CONDENSED BALANCE SHEETS - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Current assets:
Cash and cash equivalents	$ 82,462	$ 112,629
Prepaid expenses and other current assets	2,518	3,992
Total current assets	84,980	116,621
Property and equipment, net	241	1,472
Other assets	9	324
Total assets	85,230	118,417
Current liabilities:
Accounts payable	1,036	1,334
Accrued expenses	9,171	8,000
Note payable		209
Deferred revenue	94	566
Total current liabilities	10,301	10,109
Other liabilities	63	613
Total liabilities	10,364	10,722
Commitments and contingencies
Stockholders' equity:
Common stock, $0.001 par value, Authorized — 70,000 shares; Issued and outstanding — 27,179 and 24,453 shares at September 30, 2018 and December 31, 2017, respectively	27	24
Additional paid-in capital	727,064	712,165
Accumulated deficit	(652,225)	(604,494)
Total stockholders' equity	74,866	107,695
Total liabilities and stockholders' equity	85,230	118,417
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