Consolidated Balance Sheets (USD $) In Thousands, unless otherwise specified	Jun. 30, 2014	Dec. 31, 2013
Current assets:
Cash and cash equivalents	$ 81,235	$ 72,021
Restricted cash	8,500	0
Trade accounts receivable, net	5,920	6,665
Inventory	15,656	9,936
Prepaid expenses and other current assets	5,190	4,257
Total current assets	116,501	92,879
Property and equipment, net	10,960	13,011
Other assets	5,837	6,614
Total assets	133,298	112,504
Current liabilities:
Accounts payable	13,546	4,622
Accrued expenses	14,467	18,865
Accrued compensation	6,399	3,952
Common stock warrant liabilities	11,955	31,341
Deferred revenue	8,424	0
Total current liabilities	54,791	58,780
Notes Payable, Noncurrent	2,292	0
Long-term debt, less current portion	0	28,802
Deferred revenue, less current portion	7,566	0
Other long-term liabilities	331	6,496
Commitments and contingencies
Stockholders' equity:
Common stock	141	139
Additional paid-in capital	436,491	428,534
Accumulated deficit	(368,314)	(410,247)
Total stockholders’ equity	68,318	18,426
Total liabilities and stockholders’ equity	$ 133,298	$ 112,504