Fair Value Measurements (Tables)

6 Months Ended

Jun. 30, 2013

Fair Value Measurements

Schedule of the assets and liabilities measured at fair value on a recurring basis

	Balance at December 31, 2012		Level 1		Level 2		Level 3
Liabilities
Warrants to purchase preferred stock(1)	$	1,103	$	—	$	—	$	1,103
	$	1,103	$	—	$	—	$	1,103
	Balance at June 30, 2013		Level 1		Level 2		Level 3
	(unaudited)
Liabilities
Warrants to purchase preferred stock(1)	$	926	$	—	$	—	$	926
	$	926	$	—	$	—	$	926

(1) The Company used an option pricing model to determine the fair value of the warrants to purchase preferred stock.  Significant inputs included an estimate of the fair value of the Company’s preferred stock as of December 31, 2012 and actual as of June 30, 2013, the remaining contractual life of the warrant, a risk-free rate of interest, and an estimate of the Company’s stock volatility using the volatilities of guideline peer companies.  In connection with the Company’s IPO, these warrants to purchase preferred stock were adjusted to fair value through July 2, 2013 and were subsequently reclassified to additional paid-in capital (refer to note 2).

Schedule of changes in the Company's Level 3 instruments measured at fair value on a recurring basis

	Warrants to Purchase Preferred Stock
	2012			2013
	(unaudited)
Beginning balance at April 1,	$	1,121		$	1,098
Mark-to-market income	(8		)	(172		)
Ending balance at June 30,	$	1,113		$	926

	Warrants to Purchase Preferred Stock
	2012			2013
	(unaudited)
Beginning balance at January 1,	$	1,127		$	1,103
Mark-to-market income	(14		)	(177		)
Ending balance at June 30,	$	1,113		$	926

	Contingent Consideration on Acquisition(1)
	2012
	(unaudited)
Beginning balance at January 1,	$	817
Mark-to-market expenses	46
Settlement of contingent consideration	(863		)
Ending balance at June 30,	$	—

(1) On February 11, 2011, the Company acquired all of the outstanding equity of Transpera, Inc. The purchase price included contingent consideration consisting of up to 169,131 shares of the Company’s common stock payable on the one year anniversary of the closing of the acquisition based on certain performance criteria being achieved. In arriving at the value of the contingent consideration, the Company used a valuation model based on future expectations combined with management’s judgment. In the then-absence of a public trading market, the Company exercised judgment and considered numerous objective and subjective factors to determine the fair value of the Company’s common stock.