Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Current assets:
Cash and cash equivalents	$ 18,086	$ 32,804
Accounts receivable, net of allowances of $93 and $89	17,535	20,624
Inventories	12,868	6,532
Prepaid expenses and other current assets	1,697	1,687
Total current assets	50,186	61,647
Property, plant and equipment, net	84,394	78,322
Other long-term assets	89	105
Total assets	134,669	140,074
Current liabilities:
Capital leases, current portion	35	67
Accounts payable	13,065	10,684
Accrued expenses	3,987	5,568
Deferred revenue	1,043	681
Other current liabilities	154	409
Total current liabilities	18,130	17,409
Capital leases, excluding current portion	4	40
Other long-term liabilities	971	151
Total liabilities	19,105	17,600
Commitments and contingencies (Note 9)
Stockholders’ equity:
Preferred stock, $0.00001 par value; 5,000,000 shares authorized, no shares issued or outstanding at December 31, 2016 and 2015
Common stock, $0.00001 par value; 125,000,000 shares authorized, 23,369,838 shares issued and outstanding at December 31, 2016; 23,184,852 shares issued and outstanding at December 31, 2015	0	0
Additional paid-in capital	533,088	527,975
Accumulated deficit	(417,524)	(405,501)
Total stockholders’ equity	115,564	122,474
Total liabilities and stockholders’ equity	$ 134,669	$ 140,074