Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Current assets:
Cash and cash equivalents	$ 34,121	$ 13,935
Contract and other receivables	1,141	26
Prepaid materials, net	3,924	4,194
Prepaid expenses and other current assets	1,221	1,140
Total current assets	40,407	19,295
Property and equipment, net	921	7,806
Intangibles, net	266	500
Other assets	487	326
Total assets	42,081	27,927
Current liabilities:
Accounts payable	1,321	1,714
Accrued liabilities	917	1,625
Accrued compensation	1,676	1,601
Current portion of term loan, less debt issuance costs	14,631	16,575
Current portion of contract liabilities	6	2,572
Other current liabilities	3,047	2,559
Total current liabilities	21,598	26,646
Contract liabilities, less current portion	0	6
Deferred rent, less current portion	0	6,820
Other long-term liabilities	468	309
Total liabilities	22,066	33,781
Stockholders’ equity (deficit):
Common stock, $0.001 par value; 200,000,000 shares authorized, 21,018,663 and 8,818,019 shares issued and outstanding at December 31, 2019 and 2018, respectively	21	9
Additional paid-in capital	431,305	386,860
Accumulated deficit	(411,315)	(392,723)
Total stockholders’ equity (deficit)	20,015	(5,854)
Total liabilities and stockholders’ equity (deficit)	42,081	27,927
Class A-1 Convertible Preferred Stock
Stockholders’ equity (deficit):
Convertible preferred stock	1	0
Class A-2 Convertible Preferred Stock
Stockholders’ equity (deficit):
Convertible preferred stock	$ 3	$ 0