Condensed Consolidated Balance Sheets (Unaudited) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Current assets
Cash and cash equivalents	$ 32,614	$ 25,522
Accounts receivable, net	2,042	3,819
Inventory	76	883
Prepaid expenses and other current assets	2,286	992
Total current assets	37,018	31,216
Property and equipment, net	8,684	10,550
Operating lease right-of-use assets	1,756	2,452
Intangible assets, net	447	542
Goodwill	278	278
Other assets	227	472
TOTAL ASSETS	48,410	45,510
Current liabilities
Accounts payable and accrued expenses	3,924	4,148
Other current liabilities	2,509	2,106
Current portion of long-term notes payable		2,059
Deferred revenue	86	168
Total current liabilities	6,519	8,481
Common stock warrant liability	14,059	5,975
Operating lease liabilities	550	1,476
Other long-term liabilities	514	723
Long-term notes payable		1,517
Total liabilities	21,642	18,172
Commitments and Contingencies (Note 14)
STOCKHOLDERS’ EQUITY
Preferred stock - 25,000,000 shares authorized, 0 shares issued and outstanding at June 30, 2021 and December 31, 2020
Common stock – $.001 par value; 250,000,000 shares authorized; 80,742,443 and 54,857,099 shares issued and outstanding at June 30, 2021 and December 31, 2020, respectively	81	55
Additional paid-in capital	525,496	505,494
Accumulated deficit	(498,809)	(478,211)
Total stockholders’ equity	26,768	27,338
TOTAL LIABILITIES AND STOCKHOLDERS’ EQUITY	$ 48,410	$ 45,510