Consolidated Balance Sheets - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Current assets:
Cash and cash equivalents	$ 11,228	$ 18,086
Accounts receivable, net of allowances of $83 and $93	17,248	17,535
Inventories	15,132	12,868
Prepaid expenses and other current assets	1,192	1,697
Total current assets	44,800	50,186
Property, plant and equipment, net	82,719	84,394
Other long-term assets	97	89
Total assets	127,616	134,669
Current liabilities:
Accounts payable	14,169	13,065
Accrued expenses	4,112	3,987
Deferred revenue	789	1,043
Capital leases, current portion	20	35
Total current liabilities	19,090	18,130
Capital leases, excluding current portion		4
Deferred rent	1,082	971
Total liabilities	20,172	19,105
Commitments and contingencies (Note 6)
Stockholders’ equity:
Preferred stock, $0.00001 par value; 5,000,000 shares authorized, no shares issued and outstanding at March 31, 2017 and December 31, 2016
Common stock, $0.00001 par value; 125,000,000 shares authorized, 23,508,417 and 23,369,838 shares issued and outstanding at March 31, 2017 and December 31, 2016, respectively	0	0
Additional paid-in capital	534,346	533,088
Accumulated deficit	(426,902)	(417,524)
Total stockholders’ equity	107,444	115,564
Total liabilities and stockholders’ equity	$ 127,616	$ 134,669