Consolidated Statements of Cash Flows (USD $) In Thousands, unless otherwise specified	6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011
Cash flows from operating activities:
Net loss	$ (5,308)	$ (3,160)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation of property and equipment	296	198
Amortization of patent and trademark rights	5	110
Redeemable warrants valuation adjustment	(236)	(944)
Equity-based compensation	90	179
Change in assets and liabilities:
Inventories	(211)	(179)
Prepaid expenses and other current assets	106	(190)
Accounts payable	256	(140)
Accrued expenses	(476)	(676)
Net cash used in operating activities	(5,478)	(4,802)
Cash flows from investing activities:
Purchase of property, equipment and construction in progress	(3,208)	(381)
Additions to patent and trademark rights	(28)	(51)
Deposits on capital leases	7	(4)
Maturities of short-term and long-term marketable securities	7,216	7,606
Purchase of short-term and long-term marketable securities	(2,057)	(3,177)
Net cash provided by investing activities	1,930	3,993
Cash flows from financing activities:
Payments on capital leases	(25)	(31)
Proceeds from Margin Account Loan	2,640	0
Net cash provided by (used in) financing activities	2,615	(31)
Net decrease in cash and cash equivalents	(933)	(840)
Cash and cash equivalents at beginning of period	3,103	2,920
Cash and cash equivalents at end of period	2,170	2,080
Supplemental disclosures of non-cash investing and financing cash flow information:
Issuance of common stock for accounts payable and accrued expenses	133	70
Equipment acquired by capital lease	0	62
Unrealized gain on investments	655	636
Redeemable warrants valuation adjustment	236	944
Supplemental disclosure of cash flow information:
Cash paid for interest expense	$ (12)	$ (12)