CONDENSED BALANCE SHEETS - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Current assets:
Cash and cash equivalents	$ 32,611	$ 71,431
Short-term investments	8,975
Prepaid expenses and other current assets	3,488	1,376
Total current assets	45,074	72,807
Property and equipment, net	123	207
Operating lease right-of-use asset	125
Other assets	70	9
Total assets	45,392	73,023
Current liabilities:
Accounts payable	321	1,134
Accrued expenses	7,307	7,884
Operating lease liability	138
Total current liabilities	7,766	9,018
Other liabilities		11
Total liabilities	7,766	9,029
Commitments and contingencies
Stockholders' equity:
Common stock, $0.001 par value, Authorized — 70,000 shares; Issued and outstanding — 28,858 and 27,188 shares at September 30, 2019 and December 31, 2018, respectively	29	27
Additional paid-in capital	735,254	728,342
Accumulated deficit	(697,658)	(664,375)
Accumulated other comprehensive income	1
Total stockholders' equity	37,626	63,994
Total liabilities and stockholders' equity	45,392	73,023
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