Condensed Consolidated Balance Sheets (Unaudited) - USD ($)	Jun. 30, 2018	Dec. 31, 2017
Current Assets:
Cash and cash equivalents	$ 28,891,000	$ 26,754,000
Short-term marketable securities	26,358,000	45,236,000
Accounts receivable, net of allowances of $86 and $2,754, respectively	7,144,000	10,676,000
Inventories	8,828,000	10,949,000
Prepaid expenses and other current assets	1,912,000	2,216,000
Total current assets	73,133,000	95,831,000
Property and equipment, net	21,159,000	22,581,000
Intangible assets, net	2,327,000	2,624,000
Restricted cash	758,000	758,000
Other long-term assets	522,000	505,000
Total assets	97,899,000	122,299,000
Current liabilities:
Accounts payable	9,219,000	11,171,000
Accrued compensation	4,872,000	5,419,000
Current portion of long-term debt	19,009,000	7,927,000
Other current liabilities	2,710,000	3,226,000
Total current liabilities	35,810,000	27,743,000
Deferred rent	2,715,000	3,059,000
Long-term debt	9,579,000	20,099,000
Other noncurrent liabilities	146,000	241,000
Total liabilities	48,250,000	51,142,000
Stockholders' equity:
Preferred stock, $0.0001 par value; 5,000 authorized, none issued	0	0
Common stock, $0.0001 par value; 100,000 authorized; 55,753 and 55,066 shares issued and outstanding, respectively	6,000	6,000
Additional paid-in capital	493,921,000	487,525,000
Accumulated deficit	(444,329,000)	(416,383,000)
Accumulated other comprehensive income	51,000	9,000
Total stockholders’ equity	49,649,000	71,157,000
Total liabilities and stockholders’ equity	$ 97,899,000	$ 122,299,000