Statements of Cash Flows (USD $)	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Cash flows from operating activities
Net loss	$ (32,031,175)	$ (19,923,487)	$ (27,494,457)
Adjustments to reconcile net loss to cash used in operating activities:
Depreciation	1,462,238	1,697,694	2,050,507
Amortization	299,833	230,459	133,333
Amortization of warrants	1,331,549	1,652,672	2,346,027
Share-based compensation	2,487,441	2,049,606	4,229,183
Loss on asset disposal	86,278	5,039	557,152
Impairment charge	0	0	338,821
Non-cash expense (royalty income), net	(2,353,718)	(3,381,424)	(1,983,414)
Warrant adjustment	(3,416,383)	(600,816)	(911,977)
Changes in operating assets and liabilities:
Accounts receivable	2,811,531	(2,762,921)	(1,413,640)
Other receivables	28,495	65,175	290,233
Inventories	(594,576)	(1,075,075)	3,851,283
Prepaid expenses and other current assets	827,297	522,924	53,238
Other assets	(2,223)	(33,426)	93,270
Accounts payable	(3,186,001)	4,937,129	(680,723)
Accrued liabilities	(1,090,072)	(1,221,120)	(866,678)
Deferred revenue	1,775,856	(1,060,903)	(2,761,929)
Other liabilities	(5,648)	(11,271)	(138,892)
Net cash used in operating activities	(31,569,278)	(18,909,745)	(22,308,663)
Cash flows from investing activities
Purchase of equipment	(1,031,749)	(715,770)	(1,484,192)
Net cash used in investing activities	(1,031,749)	(715,770)	(1,484,192)
Cash flows from financing activities
Proceeds from term note	0	10,000,000	0
Payments under term note	(2,000,000)	(333,333)	(666,667)
Proceeds from revolving line of credit	77,109,376	58,034,809	3,000,000
Payments of revolving line of credit	(72,818,866)	(57,503,298)	(6,234,822)
Proceeds from Cowen Debt	14,317,397	0	0
Payments under Biosense	(5,540,373)	(2,071,139)	0
Proceeds from issuance of stock and warrants, net of issuance costs	239,593	16,200,745	27,885,237
Net cash provided by financing activities	11,307,127	24,327,784	23,983,748
Net increase (decrease) in cash and cash equivalents	(21,293,900)	4,702,269	190,893
Cash and cash equivalents at beginning of period	35,248,819	30,546,550	30,355,657
Cash and cash equivalents at end of period	13,954,919	35,248,819	30,546,550
Supplemental disclosures of cash flow information:
Interest paid	$ 859,494	$ 140,253	$ 864,279