Financial Instruments and Fair Value Measurements Fair Value Table (Tables)

6 Months Ended

Jun. 30, 2014

Fair Value Table [Abstract]

Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis [Table Text Block]

The fair values of the Company’s assets and liabilities, which are measured at fair value on a recurring basis, were determined using the following inputs (in thousands):

	Total			Quoted Price in Active Market (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
June 30, 2014:
Cash Equivalents, Marketable Securities and Restricted Investments:
Money market funds	$	55,092		$	55,092	$	—	$	—
Certificates of deposit	869			869		—		—
Corporate notes	137,075			—		137,075		—
Commercial paper	10,000			—		10,000		—
U.S. government treasury securities	49,366			49,366		—		—
Securities of government-sponsored entities	124,806			—		124,806		—
Total cash equivalents, marketable securities and restricted investments	$	377,208		$	105,327	$	271,881	$	—
Contingent Consideration:
Acquisition-related liabilities, current	$	(648	)	$	—	$	—	$	(648	)
Total contingent consideration	$	(648	)	$	—	$	—	$	(648	)
December 31, 2013:
Cash Equivalents, Marketable Securities and Restricted Investments:
Money market funds	$	72,514		$	72,514	$	—	$	—
Certificates of deposit	1,116			1,116		—		—
Corporate notes	103,946			—		103,946		—
Commercial paper	19,973			—		19,973		—
U.S. government treasury securities	52,390			52,390		—		—
Securities of government-sponsored entities	118,250			—		118,250		—
Total cash equivalents, marketable securities and restricted investments	$	368,189		$	126,020	$	242,169	$	—
Contingent Consideration:
Acquisition-related liabilities, current	$	(616	)	$	—	$	—	$	(616	)
Acquisition-related liabilities, non-current	$	(596	)	$	—	$	—	$	(596	)
Total contingent consideration	$	(1,212	)	$	—	$	—	$	(1,212	)

Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Table Text Block]

The following table sets forth the changes in the estimated fair value of the Company’s liabilities measured on a recurring basis using significant unobservable inputs (Level 3) (in thousands):

	Six Months Ended June 30,
	2014			2013
Fair value measurement at beginning of period	$	1,212		$	1,074
Change in fair value measurement included in operating expenses	44			15
Contingent consideration paid or settled	(608		)	—
Fair value measurement at end of period	$	648		$	1,089