Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Current assets:
Cash and cash equivalents	$ 64,349	$ 41,958
Short-term investment securities	28,125	26,943
Prepaid research and development	11,120	9,691
Other current assets	1,464	439
Total current assets	105,058	79,031
Restricted cash	1,244	1,241
Leasehold interest, net	2,249	2,294
Equipment, net	241	251
Right of use asset	7,947	0
Goodwill	799	799
Total assets	117,538	83,616
Current liabilities:
Accounts payable and accrued expenses	40,199	36,377
Other current liabilities	18,626	219
Lease liability - current portion	1,261	0
Accrued compensation	854	2,258
Total current liabilities	60,940	38,854
Deferred rent	0	1,462
Deferred revenue, net of current portion	876	914
Long-term debt	28,286	0
Lease liability - non current	8,182	0
Long-term liabilities	0	18,350
Total liabilities	98,284	59,580
Commitments and contingencies
Stockholders' equity:
Preferred stock, $0.001 par value per share (10,000,000 shares authorized, none issued and outstanding as of March 31, 2019 and December 31, 2018)	0	0
Common stock, $0.001 par value per share (150,000,000 shares authorized, 88,582,227 and 83,911,855 shares issued, 88,540,918 and 83,870,546 shares outstanding at March 31, 2019 and December 31, 2018, respectively)	89	84
Additional paid-in capital	582,900	552,531
Treasury stock, at cost, 41,309 shares at March 31, 2019 and December 31, 2018	(234)	(234)
Accumulated deficit	(563,501)	(528,345)
Total stockholders' equity	19,254	24,036
Total liabilities and stockholders' equity	$ 117,538	$ 83,616