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Condensed Consolidated Statements of Cash Flows (Unaudited) (USD $)
 3 Months Ended
Mar. 31, 2012
Mar. 31, 2011
Cash Flows From Operating Activities:    
Net loss $ (6,583,102) $ (7,243,200)
Adjustments to reconcile net loss to net cash used in operating activities:    
Depreciation of property, plant and equipment 486,275 504,740
Amortization of intangible assets 575,773 581,489
Stock-based compensation 524,055 392,174
Loss on disposal of property, plant and equipment 57,680  
Realized loss on available for sale securities   22,421
Change in fair value of common stock warrant liability (1,238,750)  
Changes in operating assets and liabilities:    
Accounts receivable 419,638 (129,923)
Inventory 2,245,528 1,075,822
Prepaid expenses and other current assets 717,034 351,209
Accounts payable, accrued expenses, product warranty reserve and other liabilities (2,121,367) (2,385,856)
Deferred revenue 1,441,497 (384,189)
Net cash used in operating activities (3,475,739) (7,215,313)
Cash Flows From Investing Activities:    
Purchase of property, plant and equipment   (966,875)
Proceeds from disposal of property, plant and equipment 57,900  
Proceeds from maturities and sales of available-for-sale securities   10,399,396
Net cash provided by investing activities 57,900 9,432,521
Cash Flows From Financing Activities:    
Purchase of treasury stock   (158,179)
Proceeds from issuance of common stock 17,685,403  
Stock issuance costs (1,891,378)  
Repayment of borrowings under line of credit (5,405,110)  
Principal payments on long-term debt   (9,956)
Net cash provided by (used in) financing activities 10,388,915 (168,135)
Effect of exchange rate changes on cash 1,064 (2,479)
Increase in cash and cash equivalents 6,972,140 2,046,594
Cash and cash equivalents, beginning of period 13,856,893 10,955,403
Cash and cash equivalents, end of period $ 20,829,033 $ 13,001,997