Consolidated Statements of Cash Flows (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011
Statement of Cash Flows [Abstract]
Net loss	$ (22,693,000)	$ (35,808,000)
Adjustments to reconcile net loss to net cash used in operations:
Depreciation	1,445,000	2,406,000
Amortization of intangible assets	184,000	185,000
Impairment of intangible assets	284,000	0
Gain on disposal of property and equipment	(79,000)	(11,000)
Realized loss on sale of short-term investments	32,000	0
Non-cash stock-based compensation expense	2,269,000	3,356,000
Inventory write-downs	1,094,000	1,563,000
Non-cash deferred rent	(118,000)	(340,000)
Change in:
Accounts receivable	(652,000)	653,000
Costs and estimated earnings in excess of billings on uncompleted contracts	58,000	67,000
Inventory	2,663,000	258,000
Other current assets	(419,000)	(221,000)
Other assets	12,000	(16,000)
Accounts payable	(4,077,000)	(532,000)
Accrued liabilities	(1,175,000)	808,000
Deferred revenue	609,000	0
Billings in excess of costs and estimated earnings on uncompleted contracts	(58,000)	75,000
Other long-term liabilities	0	(330,000)
Net cash used in operating activities	(20,621,000)	(27,887,000)
Cash flows from investing activities
Sales of investment securities	11,000	0
(Increase) decrease in restricted investment	350,000	709,000
Proceeds on sale of property and equipment	80,000	11,000
Purchases of property and equipment	(533,000)	(550,000)
Net cash provided by (used in) investing activities	(92,000)	170,000
Cash flows from financing activities
Principal payments under capital leases	(136,000)	(43,000)
Principal payments under long-term debt	0	(84,000)
Net proceeds from issuance of common stock and warrants	14,624,000	21,506,000
Net cash provided by financing activities	14,488,000	21,379,000
Net decrease in cash and cash equivalents	(6,225,000)	(6,338,000)
Cash and cash equivalents, at beginning of period	13,075,000	19,413,000
Cash and cash equivalents, at end of period	6,850,000	13,075,000
Supplemental disclosure of cash flow information
Cash paid for interest	30,000	46,000
Supplemental schedule of non-cash investing and financing activities
Other non-cash additions to property and equipment	$ 0	$ 229,000