Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Current assets:
Cash and cash equivalents	$ 112,637	$ 41,958
Short-term investment securities	27,798	26,943
Prepaid research and development	8,105	9,691
Other current assets	611	439
Total current assets	149,151	79,031
Restricted cash	1,251	1,241
Leasehold interest, net	2,129	2,294
Equipment, net	282	251
Right of use asset	9,402	0
Goodwill	799	799
Total assets	163,014	83,616
Current liabilities:
Accounts payable and accrued expenses	30,041	36,377
Other current liabilities	48,994	219
Lease liability - current portion	1,616
Accrued compensation	3,798	2,258
Total current liabilities	84,449	38,854
Deferred rent	0	1,462
Deferred revenue, net of current portion	762	914
Long-term debt	28,970	0
Lease liability - non current	10,218	0
Long-term liabilities	0	18,350
Total liabilities	124,399	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 December 31, 2019 and 2018)	0	0
Common stock, $0.001 par value per share (150,000,000 shares authorized, 109,425,243 and 83,911,855 shares issued, 109,383,934 and 83,870,546 shares outstanding at December 31, 2019 and 2018, respectively)	109	84
Additional paid-in capital	739,956	552,531
Treasury stock, at cost, 41,309 shares at December 31, 2019 and 2018	(234)	(234)
Accumulated deficit	(701,216)	(528,345)
Total stockholders' equity	38,615	24,036
Total liabilities and stockholders' equity	$ 163,014	$ 83,616