Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Current assets:
Cash and cash equivalents	$ 36,542	$ 20,079
Marketable securities	21,924	51,199
Restricted cash	584	584
Prepaid expenses and other current assets	4,644	4,240
Total current assets	63,694	76,102
Property and equipment, net	1,009	2,269
Equity method investment	7,127	7,428
Other assets	2,523	2,744
Total assets	74,353	88,543
Current liabilities:
Accounts payable, accrued expenses and other	10,339	13,677
Note payable	1,475
Deferred rent		1,118
Total current liabilities	11,814	14,795
Note payable, net of discount and current portion	13,519	14,873
Other long-term liabilities	56	56
Total liabilities	25,389	29,724
Commitments and contingencies
Stockholders’ equity:
Preferred stock, $0.01 par value: 10,000 shares authorized at March 31, 2019 and December 31, 2018; no shares issued or outstanding at March 31, 2019 or December 31, 2018
Common stock, $0.01 par value: 30,000 shares authorized at March 31, 2019 and December 31, 2018; 13,343 shares issued and outstanding at March 31, 2019 and December 31, 2018	1,334	1,334
Additional paid-in capital	581,365	580,771
Accumulated other comprehensive loss		(9)
Accumulated deficit	(533,735)	(523,277)
Total stockholders’ equity	48,964	58,819
Total liabilities and stockholders’ equity	$ 74,353	$ 88,543