Fair Value of Financial Instruments (Tables)

9 Months Ended

Sep. 30, 2013

Fair Value Disclosures [Abstract]

Schedule of Cash and Cash Equivalents, Available-for-sale Securities, Restricted Cash Reconciliation

The Company's cash and cash equivalents, short-term investments, long-term investments and restricted cash consist of the following:

	September 30, 2013
	Amortized Cost		Unrealized Gains		Unrealized Losses			Fair Value
	(in thousands)
Cash and cash equivalents:
Cash	$	25,434	$	—	$	—		$	25,434
Money market funds	5,086		—		—			5,086
Commercial paper	11,597		1		—			11,598
Total	42,117		1		—			42,118
Short-term investments:
Commercial paper	43,960		14		(1		)	43,973
Corporate bonds	9,640		7		—			9,647
Municipal bonds	1,127		—		(1		)	1,126
U.S. government agencies	4,001		1		—			4,002
Total	58,728		22		(2		)	58,748
Long-term investments:
Asset-backed securities	3,996		3		(1		)	3,998
U.S. government agencies	4,711		2		—			4,713
Corporate bonds	16,083		13		(2		)	16,094
Total	24,790		18		(3		)	24,805
Total	$	125,635	$	41	$	(5	)	$	125,671

	December 31, 2012
	Amortized Cost		Unrealized Gains		Unrealized Losses		Fair Value
	(in thousands)
Cash and cash equivalents:
Cash	$	23,419	$	—	$	—	$	23,419
Money market funds	170		—		—		170
Commercial paper	11,294		2		—		11,296
Total	34,883		2		—		34,885
Short-term investments:
Commercial paper	21,078		2		—		21,080
U.S. government agencies	62,463		4		—		62,467
Total	83,541		6		—		83,547
Restricted cash - cash	114		—		—		114
Total	$	118,538	$	8	$	—	$	118,546

Schedule of Assets Measured on Recurring Basis

lowing table sets forth by level within the fair value hierarchy the fair value of the Company's available-for-sale securities measured on a recurring basis:

	September 30, 2013
	Level 1		Level 2		Level 3		Fair Value
	(in thousands)
Commercial paper	$	—	$	55,571	$	—	$	55,571
U.S. government agencies	—		8,715		—		8,715
Municipal bonds	—		1,126		—		1,126
Corporate bonds	—		25,741		—		25,741
Asset-backed securities	—		3,998		—		3,998
Total	$	—	$	95,151	$	—	$	95,151

	December 31, 2012
	Level 1		Level 2		Level 3		Fair Value
	(in thousands)
Commercial paper	$	—	$	32,376	$	—	$	32,376
U.S. government agencies	—		62,467		—		62,467
Total	$	—	$	94,843	$	—	$	94,843

Schedule of Available-for-Sale Securities by Contractual Maturity

The following summarizes the fair value of securities classified as available-for-sale by contractual maturity:

	September 30, 2013
	Mature within One Year		After One Year through Two Years		Over Two Years		Fair Value
	(in thousands)
Commercial paper	$	55,571	$	—	$	—	$	55,571
U.S. government agencies	4,002		4,713		—		8,715
Municipal bonds	1,126		—		—		1,126
Corporate bonds	9,647		16,094		—		25,741
Asset-backed securities	—		—		3,998		3,998
Total	$	70,346	$	20,807	$	3,998	$	95,151

	December 31, 2012
	Mature within One Year		After One Year through Two Years		Over Two Years		Fair Value
	(in thousands)
Commercial paper	$	32,376	$	—	$	—	$	32,376
U.S. government agencies	62,467		—		—		62,467
Total	$	94,843	$	—	$	—	$	94,843