Condensed Consolidated Balance Sheets (Unaudited) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Current assets:
Cash and cash equivalents	$ 39,934	$ 60,599
Trade and other receivables, net	7,489	6,481
Inventories, net	5,137	5,441
Prepaid expenses and other current assets	3,398	1,680
Total current assets	55,958	74,201
Property and equipment, net	11,594	12,207
Intangible assets, net	191	204
Other assets	236	239
Total assets	67,979	86,851
Current liabilities:
Accounts payable and accrued expenses	22,088	27,631
Deferred revenue, current	700	721
Loans payable, current	6,850	4,600
Total current liabilities	29,638	32,952
Loans payable, net	40,742	42,603
Deferred revenue, net of current portion	2,405	0
Asset retirement obligations	1,250	1,216
Total liabilities	74,035	76,771
Commitments and contingencies (Note 17)
Shareholders' (deficit)/equity:
Common stock, $.001 par value. Authorized 250,000,000 shares; 24,975,139 and 24,957,309 shares issued and outstanding at March 31, 2019 and December 31, 2018, respectively	25	25
Additional paid-in capital	72,873	71,431
Accumulated deficit	(78,954)	(61,376)
Total shareholders' (deficit)/equity	(6,056)	10,080
Total liabilities and shareholders' (deficit)/equity	$ 67,979	$ 86,851