Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Current assets:
Cash and cash equivalents	$ 299	$ 1,412
Marketable securities- unrestricted	1,526	695
Funds receivable from sale of New Jersey net operating loss	859
Accounts receivable	235	24
Assets held for sale		764
Prepaid expenses and other current assets	880	610
Total current assets	3,799	3,505
Property and equipment, net	7,782	8,586
Patent and trademark rights, net	912	858
Other assets	1,352	1,258
Total assets	13,845	14,207
Current liabilities:
Accounts payable	680	741
Accrued expenses	1,005	1,966
Convertible note payable	3,408
Current portion of financing obligation	199
Total current liabilities	5,292	2,707
Long-term liabilities:
Note payable		1,835
Financing obligation arising from sale leaseback transaction (Note 19)	2,318
Redeemable warrants	1,061	962
Commitments and contingencies (Notes 9,11,12,14, 15 and 19)
Stockholders' equity:
Preferred stock, par value $0.01 per share, authorized 5,000,000; issued and outstanding; none
Common stock, par value $0.001 per share, authorized 350,000,000 shares; issued and outstanding 48,734,712 and 32,884,786, respectively	49	33
Additional paid-in capital	323,701	317,419
Other comprehensive income (loss)	(3)	11
Accumulated deficit	(318,573)	(308,760)
Total stockholders' equity	5,174	8,703
Total liabilities and stockholders' equity	$ 13,845	$ 14,207