Fair Value Measurements (Tables)

6 Months Ended

Jun. 30, 2015

Fair Value Measurements [Abstract]

Fair Value, by Balance Sheet Grouping [Table Text Block]

	Assets and Liabilities at Fair Value as of June 30, 2015
	Level 1		Level 2		Level 3		Total
	(in thousands)
Assets
Cash and cash equivalents	$	9,744	$	—	$	—	$	9,744
Short-term investments	272,186		553		—		272,739
Total cash and cash equivalents and investments	$	281,930	$	553	$	—	$	282,483
Liabilities
Other long-term liabilities	$	—	$	—	$	18,629	$	18,629
Total liabilities	$	—	$	—	$	18,629	$	18,629

	Assets and Liabilities at Fair Value as of December 31, 2014
	Level 1		Level 2		Level 3		Total
	(in thousands)
Assets
Cash and cash equivalents	$	137,266	$	—	$	—	$	137,266
Short-term investments	201,521		552		—		202,073
Total cash and cash equivalents and investments	$	338,787	$	552	$	—	$	339,339
Liabilities
Other long-term liabilities	$	—	$	—	$	17,638	$	17,638
Total liabilities	$	—	$	—	$	17,638	$	17,638

Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Table Text Block]

	Other Long-term Liabilities
	(in thousands)
Balance at December 31, 2014	$	17,638
Change in valuation of purchase consideration payable to former Symphony Icon stockholders	1,741
Payment of contingent payment obligation with cash	(750		)
Balance at June 30, 2015	$	18,629
Balance at December 31, 2013	$	27,710
Change in valuation of purchase consideration payable to former Symphony Icon stockholders	1,590
Balance at June 30, 2014	$	29,300