Consolidated Balance Sheets - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Current assets:
Cash and cash equivalents	$ 3,322	$ 3,327
Accounts receivable, net of allowances of $2,661 and $2,877	22,166	25,565
Inventories	13,099	7,318
Prepaid expenses and other current assets	1,320	1,041
Total current assets	39,907	37,251
Property, plant and equipment, net	57,319	61,699
Operating lease right-of-use assets	4,461
Other long-term assets	75	73
Total assets	101,762	99,023
Current liabilities:
Accounts payable	10,028	12,392
Accrued expenses	4,045	3,864
Revolving line of credit	2,885	4,181
Deferred revenue	6,915	2,629
Operating lease liabilities	1,057
Total current liabilities	24,930	23,066
Deferred rent		1,218
Prepayment liability	9,784	4,485
Deferred revenue long-term	1,942
Operating lease liabilities long-term	4,762
Total liabilities	41,418	28,769
Commitments and contingencies (Note 7)
Stockholders’ equity:
Preferred stock, $0.00001 par value; 5,000,000 shares authorized, no shares issued and outstanding at June 30, 2019 and December 31, 2018
Common stock, $0.00001 par value; 125,000,000 shares authorized, 24,300,264 and 23,973,517 shares issued and outstanding at June 30, 2019 and December 31, 2018, respectively	0	0
Additional paid-in capital	543,249	541,839
Accumulated deficit	(482,905)	(471,585)
Total stockholders’ equity	60,344	70,254
Total liabilities and stockholders’ equity	$ 101,762	$ 99,023