Consolidated Balance Sheets - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Current assets:
Cash and cash equivalents	$ 7,305	$ 18,086
Accounts receivable, net of allowances of $98 and $93	17,106	17,535
Inventories	13,992	12,868
Prepaid expenses and other current assets	1,478	1,697
Total current assets	39,881	50,186
Property, plant and equipment, net	78,073	84,394
Other long-term assets	84	89
Total assets	118,038	134,669
Current liabilities:
Accounts payable	8,886	13,065
Accrued expenses	4,685	3,987
Deferred revenue	1,608	1,043
Capital leases, current portion	4	35
Total current liabilities	15,183	18,130
Capital leases, excluding current portion		4
Deferred rent	1,332	971
Total liabilities	16,515	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 September 30, 2017 and December 31, 2016
Common stock, $0.00001 par value; 125,000,000 shares authorized, 23,637,115 and 23,369,838 shares issued and outstanding at September 30, 2017 and December 31, 2016, respectively	0	0
Additional paid-in capital	536,985	533,088
Accumulated deficit	(435,462)	(417,524)
Total stockholders’ equity	101,523	115,564
Total liabilities and stockholders’ equity	$ 118,038	$ 134,669