Consolidated Balance Sheets (USD $) In Thousands, unless otherwise specified	Sep. 30, 2014	Dec. 31, 2013
Current assets:
Cash and cash equivalents	$ 44,215	$ 60,033
Accounts receivable, net of allowance for doubtful accounts of $20 and $5, respectively	2	28
Inventory	610	597
Prepaid expenses and other current assets	480	1,202
Total current assets	45,307	61,860
Property and equipment, net of accumulated depreciation of $994 and $735, respectively	1,749	1,701
Intangible assets, net of accumulated amortization of $1,516 and $1,102, respectively	4,824	5,238
Other assets	1	215
Total assets	51,881	69,014
Current liabilities:
Accounts payable	1,054	2,958
Accrued expenses	2,041	487
Deferred revenue	479	148
Total current liabilities	3,574	3,593
Warrant liability	14,081	15,216
Other long term liabilities	679	539
Total liabilities	18,334	19,348
Stockholders' equity:
Preferred stock, $0.001 par value; 5,000,000 shares authorized; no shares outstanding
Common stock, $0.001 par value; 100,000,000 shares authorized; 40,856,815 and 39,832,225 shares issued and outstanding, respectively	41	40
Additional paid-in capital	142,852	136,694
Accumulated deficit	(109,346)	(87,068)
Total stockholders' equity	33,547	49,666
Total liabilities and stockholders' equity	$ 51,881	$ 69,014