Condensed Consolidated Balance Sheets (Unaudited) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Current assets
Cash and cash equivalents	$ 30,504	$ 10,218
Short-term investments		19,022
Accounts receivable, net	2,115	1,731
Inventory	281	252
Prepaid expenses and other current assets	2,453	1,264
Total current assets	35,353	32,487
Property and equipment, net	12,729	14,911
Operating lease right-of-use assets	3,559	4,590
Intangible assets, net	636	731
Goodwill	278	278
Other assets	599	602
TOTAL ASSETS	53,154	53,599
Current liabilities
Accounts payable and accrued expenses	5,050	7,095
Other current liabilities	2,644	2,338
Current portion of long-term notes payable	1,436	528
Deferred revenue	97	98
Total current liabilities	9,227	10,059
Common stock warrant liability	8,736
Operating lease liabilities	2,192	2,994
Other long-term liabilities	1,022	1,630
Long-term notes payable	2,410
Total liabilities	23,587	14,683
Commitments and Contingencies (Note 14)
STOCKHOLDERS’ EQUITY
Preferred stock - 25,000,000 shares authorized, 0 shares issued and outstanding at June 30, 2020 and December 31, 2019
Common stock – $.001 par value; 250,000,000 shares authorized; 38,496,910 and 27,374,653 shares issued and outstanding at June 30, 2020 and December 31, 2019, respectively	38	27
Additional paid-in capital	490,603	474,174
Accumulated other comprehensive income		72
Accumulated deficit	(461,074)	(435,357)
Total stockholders’ equity	29,567	38,916
TOTAL LIABILITIES AND STOCKHOLDERS’ EQUITY	$ 53,154	$ 53,599