CONSOLIDATED BALANCE SHEETS (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Current assets:
Cash and cash equivalents	$ 22,781	$ 29,485
Short-term investments	28,513	28,191
Accounts receivable, net of allowance of $0 at December 31, 2014 and 2013	5,493	6,125
Inventories	14,956	13,063
Prepaid expenses	1,210	848
Other current assets	1,932	442
Total current assets	74,885	78,154
Non-current assets:
Property and equipment, net	3,781	2,189
Goodwill	1,316	1,316
Intangible assets, net	1,142	1,344
Restricted cash	508	308
Other assets	144	70
Total assets	81,776	83,381
Current liabilities:
Accounts payable	9,882	5,674
Accrued liabilities	8,444	9,813
Deferred revenue-current	376	181
Debt-current	0	3,366
Warrant liability	10,485	20,390
Total current liabilities	29,187	39,424
Non-current liabilities:
Debt-non-current	9,872	0
Deferred income taxes	115	89
Other non-current liabilities	1,081	1,073
Total liabilities	40,255	40,586
Commitments and contingencies
Stockholders' equity:
Common stock, $0.001 par value 225,000 and 112,500 shares authorized; 80,404 and 71,859 shares issued and outstanding at December 31, 2014 and 2013, respectively	80	72
Additional paid-in capital	583,416	545,905
Accumulated other comprehensive (loss) income	(31)	7
Accumulated deficit	(541,944)	(503,189)
Total stockholders' equity	41,521	42,795
Total liabilities and stockholders' equity	$ 81,776	$ 83,381