UNAUDITED CONDENSED CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Current assets:
Cash and cash equivalents	$ 22,196	$ 26,268
Accounts receivable	3	0
Unbilled revenue receivable	0	3
Receivable from related party	3	10
Prepaid expenses and other assets	1,414	1,382
Total current assets	23,616	27,663
Property and equipment, net	977	1,061
Other noncurrent assets	591	32
Total assets	25,184	28,756
Current liabilities:
Current portion of long-term debt	4,807	0
Accounts payable	848	500
Accrued expenses and other current liabilities	1,591	1,543
Current portion of deferred revenue	975	0
Total current liabilities	8,221	2,043
Long-term debt, net	0	4,925
Common stock warrant liability	428	797
Other noncurrent liabilities	380	39
Total liabilities	9,029	7,804
Stockholders’ equity:
Common stock, $0.0001 par value per share; 200,000,000 shares authorized, 44,358,000 issued and outstanding, March 31, 2019 and December 31, 2018	4	4
Additional paid-in capital	76,431	75,942
Accumulated deficit	(60,280)	(54,994)
Total stockholders' equity	16,155	20,952
Total liabilities and stockholders’ equity	$ 25,184	$ 28,756