Equity Transactions (Detail) (USD $)			9 Months Ended
	Sep. 30, 2012	Dec. 31, 2011	Sep. 30, 2012 Preferred Stock		Sep. 30, 2012 Common Stock		Sep. 30, 2012 Additional Paid-in Capital
Stockholders Equity Note [Line Items]
Beginning Balances (in shares)			1,321,514		13,812,490
Beginning Balances	$ 11,402,761	$ 10,704,066	$ 1,322		$ 13,969		$ 59,289,516
Exercise of stock options and warrants (in shares)					179,270
Exercise of stock options and warrants					179		64,321
Stock-based compensation (in shares)
Stock-based compensation							1,411,672
Stock dividends to Carilion Clinic (in shares)				[1]		[1]		[1]
Stock dividends to Carilion Clinic					59	[1]	94,915	[1]
Issuance of common stock other (in shares)					14,091	[2]
Issuance of common stock other					14	[2]	19,986	[2]
Ending Balances (in shares)			1,321,514		14,005,851
Ending Balances	$ 11,402,761	$ 10,704,066	$ 1,322		$ 14,221		$ 60,880,410

[1] The stock dividends payable in connection with Carilion Clinic's Series A Preferred Stock will be issued subsequent to September 30, 2012. For the period from January 12, 2010, the original issue date of the Series A Preferred Stock, through September 30, 2012, the Series A Preferred Stock issued to Carilion has accrued $583,070 in dividends. The accrued and unpaid dividends as of September 30, 2012 will be paid by the issuance of 215,410 shares of our common stock upon Carilion's written request.

[2] Represents shares of common stock issued to one director in lieu of cash fees for committee chairmanship.