Consolidated Statements of Cash Flows (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Cash flows from operating activities:
Net loss	$ (16,225)	$ (17,354)	$ (9,015)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation of property and equipment	671	643	465
Amortization and abandonment of patent and trademark rights	196	40	165
Redeemable warrants valuation adjustment	(281)	(85)	(2,425)
Equity based compensation (stock option, warrant and service expense)	376	356	377
Other-than-temporary impairment of marketable securities	800	9	69
Inventory reserve	453	1,023	0
Changes in assets and liabilities:
Inventories	0	(579)	(110)
Prepaid expenses and other assets	(36)	200	(247)
Accounts payable	(617)	860	424
Accrued expenses	(2,167)	1,751	201
Net cash used in operating activities	(16,830)	(13,136)	(10,096)
Cash flows from investing activities:
Purchases of property, equipment and construction in progress	(898)	(5,755)	(1,802)
Additions to patent and trademark rights	(242)	(211)	(234)
Office rental deposit	(71)	0	0
Deposits on capital leases refunded (paid)	0	6	(4)
Maturities of short-term and long-term marketable securities	23,479	22,658	20,896
Purchase of short-term and long-term marketable securities	0	(32,765)	(10,201)
Net cash (used in) provided by investing activities	22,268	(16,067)	8,655
Cash flows from financing activities:
Proceeds from sale of common stock, net of issuance costs	249	23,003	0
Payments on capital leases	(45)	(47)	(71)
Proceeds from (payments on) Margin Account Loan	(7,051)	5,356	1,695
Net cash provided by (used in) financing activities	(6,847)	28,312	1,624
Net increase (decrease) in cash and cash equivalents	(1,409)	(891)	183
Cash and cash equivalents at beginning of year	2,212	3,103	2,920
Cash and cash equivalents at end of year	803	2,212	3,103
Supplemental disclosures of non-cash investing and financing cash flow information:
Issuance of common stock for accounts payable and accrued expenses	269	384	71
Equipment acquired by capital leases	0	0	62
Unrealized gain (loss) on marketable securities	(71)	346	(585)
Supplemental disclosure of cash flow information:
Capitalized construction interest	143	85	0
Cash paid for interest expense	$ 16	$ 24	$ 41