Consolidated Balance Sheets (USD $) In Thousands, unless otherwise specified	Mar. 31, 2014	Dec. 31, 2013
Current assets:
Cash and cash equivalents	$ 50,684	$ 72,021
Trade accounts receivable, net	11,680	6,665
Inventory, net	14,854	9,936
Prepaid expenses and other current assets	3,767	4,257
Total current assets	80,985	92,879
Property and equipment, net	12,310	13,011
Other assets	6,685	6,614
Total assets	99,980	112,504
Current liabilities:
Accounts payable	10,569	4,622
Accrued expenses	18,726	18,865
Common stock warrant liabilities	22,156	31,341
Long-term Debt, Current Maturities	9,579	0
Deferred Revenue, Current	5,963	0
Accrued compensation	3,789	3,952
Total current liabilities	70,782	58,780
Long-term debt, less current portion	19,313	28,802
Other long-term liabilities	7,466	6,496
Commitments and contingencies
Stockholders' equity:
Common stock	140	139
Additional paid-in capital	433,458	428,534
Accumulated deficit	(431,179)	(410,247)
Total stockholders’ equity	2,419	18,426
Total liabilities and stockholders’ equity	$ 99,980	$ 112,504