Consolidated Statements of Cash Flows (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Net loss	$ (35,808)	$ (47,460)	$ (39,529)
Adjustments to reconcile net loss to net cash used in operations:
Depreciation	2,406	1,731	1,138
Amortization of intangible assets	185	32	2
Gain on disposal of property and equipment	(11)	0	0
Realized loss on sale of short-term investments	0	127	0
Non-cash stock-based compensation expense	3,356	3,450	3,373
Loss (gain) on derivative instruments	0	(842)	506
Inventory write-downs	1,563	9,579	1,257
Non-cash deferred rent	(340)	(276)	(276)
Change in:
Accounts receivable	653	(203)	(376)
Costs and estimated earnings in excess of billings on uncompleted contracts	67	(67)	625
Inventory	258	(14,728)	(658)
Other current assets	(221)	187	115
Other assets	(16)	15	(3)
Accounts payable	(532)	2,591	1,477
Accrued liabilities	808	(358)	646
Billings in excess of costs and estimated earnings on uncompleted contracts	75	26	(7)
Other long-term liabilities	(330)	0	0
Net cash used in operating activities	(27,887)	(46,196)	(31,710)
Cash flows from investing activities
Sales of investment securities	0	2,573	0
Purchases of restricted investment securities	0	(305)	0
(Increase) decrease in restricted investment	709	(1)	143
Proceeds on sale of property and equipment	11	0	0
Purchases of property and equipment	(550)	(1,886)	(1,360)
Net cash provided by (used in) investing activities	170	381	(1,217)
Cash flows from financing activities
Principal payments under capital leases	(43)	(65)	(60)
Principal payments under long-term debt	(84)	(78)	(71)
Net proceeds from issuance of common stock and warrants	21,506	22,346	50,550
Net cash provided by financing activities	21,379	22,203	50,419
Net increase (decrease) in cash and cash equivalents	(6,338)	(23,612)	17,492
Cash and cash equivalents, at beginning of period	19,413	43,025	25,533
Cash and cash equivalents, at end of period	13,075	19,413	43,025
Supplemental disclosure of cash flow information
Cash paid for interest	46	62	68
Supplemental schedule of non-cash investing and financing activities
Property and equipment acquired under capital leases	0	0	95
Other non-cash additions to property and equipment	229	101	85
Issuance of common stock for payment of intellectual property	$ 0	$ 1,700	$ 0