Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Current assets
Cash and cash equivalents	$ 16,862	$ 5,837
Accounts receivable	0	1,079
Inventory	0	192
Other current assets	698	729
Total current assets	17,560	7,837
Property and equipment, net	1,883	1,849
Operating lease right-of-use asset	946	1,308
Restricted cash	435	435
Intangible assets	164	221
Other assets	18	186
Total assets	21,006	11,836
Current liabilities
Accounts payable	630	1,871
Accrued liabilities	495	2,045
Deferred revenue	0	21
Contract liabilities	7,765	9,755
Other current liabilities	0	83
Current portion of long-term debt	431	0
Current portion of operating lease liability	676	656
Current portion of finance lease obligations	31	25
Total current liabilities	10,028	14,456
Long-term debt, net of current portion	1,151	0
Operating lease liability, net of current portion	774	1,348
Finance lease obligations, net of current portion	44	9
Total liabilities	11,997	15,813
Commitments and contingencies (Note 13)
Shareholders' equity (deficit)
Preferred stock, par value $0.001; 25,000 shares authorized; zero and zero shares issued and outstanding	0	0
Common stock, par value $0.001; 210,000 shares authorized; 152,926 and 125,803 shares issued and outstanding at December 31, 2020 and 2019, respectively	153	126
Additional paid-in capital	601,224	568,496
Subscriptions receivable	(6,135)	0
Accumulated deficit	(586,233)	(572,599)
Total shareholders' equity (deficit)	9,009	(3,977)
Total liabilities and shareholders' equity (deficit)	21,006	11,836
Reconciliation of cash, cash equivalents, and restricted cash balances
Cash and cash equivalents	16,862	5,837
Restricted cash	435	435
Cash, cash equivalents, and restricted cash	$ 17,297	$ 6,272