Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Current assets:
Cash and cash equivalents	$ 19,143	$ 14,463
Marketable securities	0	40,008
Accounts receivable, net	1,533	865
Inventory, net	966
Prepaid expenses and other current assets	2,283	1,449
Total current assets	23,925	56,785
Property and equipment, net	12,447	14,243
Right of use asset	949	138
Other non-current assets	2,012	1,896
Total assets	39,333	73,062
Current liabilities:
Long-term debt, current portion	16,833
Accounts payable	8,707	3,867
Accrued expenses	3,563	3,348
Lease liability, current portion	175	138
Total current liabilities	29,278	7,353
Lease liability, long-term	784
Long-term debt		16,381
Total liabilities	30,062	23,734
Commitments and contingencies (Note 11)
Stockholders' equity
Common stock, $.0001 par value, 150,000,000 shares authorized, 121,396,033 and 87,563,753 issued and outstanding at December 31, 2021 and December 31, 2020, respectively	12	9
Additional paid-in capital	396,376	361,539
Accumulated other comprehensive income		3
Accumulated deficit	(387,117)	(312,223)
Total stockholders' equity	9,271	49,328
Total liabilities and stockholders' equity	$ 39,333	$ 73,062