Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Current assets:
Cash and cash equivalents	$ 49,794	$ 93,441
Marketable securities	35,052
Restricted cash	584
Prepaid expenses and other current assets	1,837	1,605
Total current assets	87,267	95,046
Restricted cash		674
Property and equipment, net	3,188	6,467
Equity method investment	8,893	10,551
Other assets	4,568	4,588
Total assets	103,916	117,326
Current liabilities:
Accounts payable, accrued expenses and other	19,049	17,606
Accrued intraperiod tax allocation	1,340
Deferred rent	1,676	2,171
Total current liabilities	22,065	19,777
Deferred rent, net of current portion		1,209
Notes payable, net of discount	14,752
Other long-term liabilities	56	56
Total liabilities	36,873	21,042
Commitments and contingencies (Note 5)
Stockholders’ equity:
Preferred stock, $0.01 par value: 10,000 shares authorized at September 30, 2018 and December 31, 2017; no shares issued or outstanding at September 30, 2018 or December 31, 2017
Common stock, $0.01 par value: 30,000 shares authorized at September 30, 2018 and 20,000 shares authorized at December 31, 2017; 13,343 shares issued and outstanding at September 30, 2018 and December 31, 2017	1,334	1,334
Additional paid-in capital	580,047	577,721
Accumulated deficit	(514,333)	(482,771)
Accumulated other comprehensive loss	(5)
Total stockholders’ equity	67,043	96,284
Total liabilities and stockholders’ equity	$ 103,916	$ 117,326