Statements Of Cash Flows (USD $)	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011
Cash flows from operating activities
Net loss	$ (5,812,912)	$ (9,549,933)
Adjustments to reconcile net loss to cash used in operating activities:
Depreciation	344,455	358,584
Amortization	74,958	74,958
Amortization of warrants	511,079	328,327
Share-based compensation	937,323	818,361
Non-cash royalty (income), net		(796,995)
Warrant adjustment	188,070	(20,346)
Changes in operating assets and liabilities:
Accounts receivable	810,557	698,903
Other receivables	20,642	(2,004)
Inventories	(1,178,943)	(600,862)
Prepaid expenses and other current assets	(551,281)	(160,780)
Other assets	(875)	(5,251)
Accounts payable	392,913	(1,431,086)
Accrued liabilities	20,829	692,615
Deferred revenue	25,318	(416,407)
Other liabilities	(1,533)	(2,770)
Net cash used in operating activities	(4,219,400)	(10,014,686)
Cash flows from investing activities
Purchase of equipment	(82,272)	(332,957)
Net cash used in investing activities	(82,272)	(332,957)
Cash flows from financing activities
Proceeds from term note
Payments under term note	(1,000,000)
Proceeds from revolving line of credit	20,695,969	17,100,000
Payments of revolving line of credit	(18,334,786)	(11,000,000)
Payments of Cowen Debt	(586,629)
Payments of Biosense Debt		(697,470)
Proceeds from issuance of stock and warrants, net of issuance costs	40,898	91,213
Net cash provided by financing activities	815,452	5,493,743
Net decrease in cash and cash equivalents	(3,486,220)	(4,853,900)
Cash and cash equivalents at beginning of period	13,954,919	35,248,819
Cash and cash equivalents at end of period	$ 10,468,699	$ 30,394,919