Financial Instruments (Tables)

3 Months Ended

Mar. 31, 2015

The table below includes a rollforward of the balance sheet amounts for financial instruments classified by the Company within Level 3 of the valuation hierarchy for the three months ended March 31, 2015 (in thousands):



	Contingent Consideration
BALANCE AT DECEMBER 31, 2014	$	968
Amortization of interest and change in fair value on contingent consideration	(101		)
BALANCE AT MARCH 31, 2015	$	867

Fair value of asset measured on a recurring basis

The fair value of the Company’s financial assets and liabilities measured at fair value on a recurring basis was determined using the following inputs at March 31, 2015 (in thousands):



	Fair Value Measurements at Reporting Date Using
			Quoted Prices in Active Markets for Identical Assets		Significant Other Observable Inputs		Significant Unobservable Inputs
	Total		(Level 1)		(Level 2)		(Level 3)
Assets:
Money market funds ⁽¹⁾	$	3,034	$	3,034	$	—	$	—
U.S. government securities⁽²⁾	30,238		—		30,238		—
Total	$	33,272	$	3,034	$	30,238	$	—

Liabilities:
Contingent consideration	$	867	$	—	$	—	$	867
Total	$	867	$	—	$	—	$	867

The fair value of the Company’s financial assets and liabilities measured at fair value on a recurring basis was determined using the following inputs at December 31, 2014 (in thousands):



	Fair Value Measurements at Reporting Date Using
			Quoted Prices in Active Markets for Identical Assets		Significant Other Observable Inputs		Significant Unobservable Inputs
	Total		(Level 1)		(Level 2)		(Level 3)
Assets:
Money market funds ⁽¹⁾	$	9,023	$	9,023	$	—	$	—
U.S. government securities⁽²⁾	30,230		—		30,230		—
Total	$	39,253	$	9,023	$	30,230	$	—

Liabilities:
Contingent consideration	$	968	$	—	$	—	$	968
Total	$	968	$	—	$	—	$	968

⁽¹⁾ Included in cash and cash equivalents in the Company’s condensed consolidated balance sheets


⁽²⁾	Represents the portfolio of available for sale securities that is included in restricted investments and short-term investments in the Company’s condensed consolidated balance sheets

Fair value of short term investment unrealized holdings and gains

As of March 31, 2015, the amortized cost basis, aggregate fair value, and gross unrealized holding gains and losses of the Company’s short-term investments by major security type were as follows (in thousands):



	Amortized Cost		Aggregate Fair Value		Unrealized Holding Gains		Unrealized Holding Losses
U.S. government securities	$	30,237	$	30,238	$	1	$	—

The amortized cost basis, aggregate fair value and gross unrealized holding gains and losses for the Company’s available-for-sale short-term investments, by major security type, were as follows as of December 31, 2014 (in thousands):



	Amortized Cost		Aggregate Fair Value		Unrealized Holding Gains		Unrealized Holding Losses
U.S. government securities	$	30,237	$	30,230	$	—	$	7