Consolidated Balance Sheets (USD $) In Thousands, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012
Current assets:
Cash and cash equivalents	$ 16,875	$ 31,346
Accounts receivable, net of allowance for doubtful accounts of $18 and $25, respectively	45	62
Inventory	574	477
Deferred equity costs	274
Prepaid expenses	1,404	1,271
Total current assets	19,172	33,156
Property and equipment, net of accumulated depreciation of $714 and $434, respectively	1,540	1,658
Other assets	215
Intangible assets, net	5,376	5,789
Total assets	26,303	40,603
Current liabilities:
Accounts payable	1,170	921
Accrued expenses	1,317	494
Deferred revenue	132	139
Total current liabilities	2,619	1,554
Warrant liability	205	374
Other long-term liabilities	493	344
Total liabilities	3,317	2,272
Commitments
Shareholders' equity:
Common stock, $0.001 par value; 100,000,000 and 1,100,000,000 shares authorized at September 30, 2013 and December 31, 2012, respectively; 27,520,527 and 26,229,909 shares issued and outstanding at September 30, 2013 and December 31, 2012, respectively	28	26
Common stock-subscription receivable		(2,004)
Additional paid-in capital	120,014	112,384
Accumulated deficit	(97,056)	(72,075)
Total shareholders' equity	22,986	38,331
Total liabilities and shareholders' equity	$ 26,303	$ 40,603