Organization and Summary of Significant Accounting Policies - Additional Information (Detail) (USD $)
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1 Months Ended | 3 Months Ended | 12 Months Ended | 1 Months Ended | 12 Months Ended | 1 Months Ended | 12 Months Ended | 12 Months Ended | 1 Months Ended | ||||||||||||||
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Apr. 21, 2009
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Mar. 31, 2009
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Dec. 31, 2012
Segment
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Dec. 31, 2011
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Dec. 31, 2010
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Dec. 31, 2009
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Dec. 31, 2012
Patents
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Dec. 31, 2012
Stock Option and Warrant
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Dec. 31, 2011
Stock Option and Warrant
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Dec. 31, 2010
Stock Option and Warrant
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Jan. 31, 2010
Hansen
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Dec. 31, 2012
Hansen
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Jan. 31, 2010
Carilion Clinic
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Dec. 31, 2012
Carilion Clinic
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Dec. 31, 2011
Carilion Clinic
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Dec. 31, 2010
Carilion Clinic
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May 31, 2008
Carilion Clinic
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Jan. 31, 2010
Carilion Clinic
Maximum
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Jan. 31, 2010
Carilion Clinic
Before Amendment
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Dec. 31, 2010
Carilion Clinic
Before Amendment
Minimum
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Dec. 31, 2010
Carilion Clinic
Before Amendment
Maximum
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Jan. 31, 2010
Carilion Clinic
After Amendment
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Jan. 31, 2010
Carilion Clinic
Series A Convertible Preferred Stock
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Significant Accounting Policies [Line Items] | |||||||||||||||||||||||
Number of operating segments | 2 | ||||||||||||||||||||||
Issuance of common stock, legal settlement (in shares) | 1,247,330 | 1,200,000 | |||||||||||||||||||||
Damages awarded to the plaintiff | $ 36,300,000 | ||||||||||||||||||||||
Litigation settlement agreement date | December 11, 2009 | ||||||||||||||||||||||
Litigation settlement | 36,300,000 | ||||||||||||||||||||||
Litigation settlement accrued | 9,700,000 | ||||||||||||||||||||||
Senior convertible Promissory Notes principal amount converted | 5,000,000 | ||||||||||||||||||||||
Accrued interest converted | 1,200,000 | ||||||||||||||||||||||
Preferred stock issued in exchange of notes payable, shares | 1,321,514 | ||||||||||||||||||||||
Warrants issued in exchange of notes payable, shares | 356,000 | 356,000 | |||||||||||||||||||||
Warrant exercise price | 0.01 | 2.50 | 7.98 | 7.98 | 2.50 | ||||||||||||||||||
Warrant exercisable date | Feb. 01, 2013 | Dec. 31, 2020 | |||||||||||||||||||||
Warrant expiration date | Dec. 31, 2020 | ||||||||||||||||||||||
Percentage of Dividend Payable On Series A Convertible Preferred Stock | 6.00% | ||||||||||||||||||||||
Preferred stock liquidation preference value | 6,200,000 | ||||||||||||||||||||||
Dividend on preferred stock, shares of common stock issuable | 79,233 | 79,233 | 76,649 | 235,233 | |||||||||||||||||||
Conversion of stock description | Each share of Series A Convertible Preferred Stock may be converted into one share of our common stock at the option of the holder. | ||||||||||||||||||||||
Allowance for uncollectible receivables | 0 | 22,372 | 22,000 | ||||||||||||||||||||
Finite lived intangible asset, useful life | 5 years | ||||||||||||||||||||||
Research, development, and engineering | 2,558,417 | 2,674,730 | 1,694,643 | ||||||||||||||||||||
Inventory Reserves | $ 108,649 | $ 172,902 | |||||||||||||||||||||
Antidilutive securities excluded from computation of earnings per share amount | 2,400,000 | 2,500,000 | 6,500,000 |