Stock Warrants

12 Months Ended

Dec. 31, 2012

Stock Warrants

Stock Warrants

15. Stock Warrants

        The following is a description of the common and convertible preferred stock warrant activity of the Company:

(in thousands, except per share amounts)	Warrants for the purchase of common stock			Weighted average exercise price		Warrants for the purchase of convertible preferred stock			Weighted average exercise price
Balance—December 31, 2009		2,937			2.35		317		$	3.42
Exercised		—					(11	)	$	1.89
Balance—December 31, 2010		2,937			2.93		306		$	3.48
Expired		(1	)		2.47		—			—
Exercised		(296	)		2.46		(4	)	$	1.89
Balance—December 31, 2011		2,640		$	2.98		302		$	3.50
Conversion		302		$	3.50		(302	)	$	3.50
Expired		—			—		—			—
Exercised		(100	)	$	2.63		—			—
Balance—December 31, 2012		2,842		$	3.05		—			—

        During 2012, warrants to purchase 100,000 shares of common stock were cashless exercised and 71,000 shares of common stock were issued.

        During 2010, 2,596,000 warrants held by a related party stockholder were modified to extend the expiration dates by 4 years and increase the exercise prices from $2.12 and $2.47 to $3.00 per share. The modification was valued using a Black-Scholes option valuation model and the Company accounted for the $1,803,000 of incremental value within additional paid-in capital.