Fair Value Measurements (Tables)

3 Months Ended

Mar. 31, 2016

Fair Value Measurements [Abstract]

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

	Assets and Liabilities at Fair Value as of March 31, 2016
	Level 1		Level 2		Level 3		Total
	(in thousands)
Assets
Cash and cash equivalents	$	21,682	$	2,999	$	—	$	24,681
Short-term investments	434,803		17,662		—		452,465
Total cash and cash equivalents and investments	$	456,485	$	20,661	$	—	$	477,146
Liabilities
Accrued liabilities	$	—	$	—	$	12,979	$	12,979
Other long-term liabilities	—		—		10,801		10,801
Total liabilities	$	—	$	—	$	23,780	$	23,780

	Assets and Liabilities at Fair Value as of December 31, 2015
	Level 1		Level 2		Level 3		Total
	(in thousands)
Assets
Cash and cash equivalents	$	200,526	$	2,463	$	—	$	202,989
Short-term investments	312,888		5,475		—		318,363
Total cash and cash equivalents and investments	$	513,414	$	7,938	$	—	$	521,352
Liabilities
Accrued liabilities	$	—	$	—	$	12,453	$	12,453
Other long-term liabilities	—		—		10,362		10,362
Total liabilities	$	—	$	—	$	22,815	$	22,815

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

Balance at December 31, 2015	$	22,815
Change in valuation of purchase consideration payable to former Symphony Icon stockholders	965
Balance at March 31, 2016	$	23,780
Balance at December 31, 2014	$	17,638
Change in valuation of purchase consideration payable to former Symphony Icon stockholders	1,753
Payment of contingent payment obligation with cash	(750		)
Balance at March 31, 2015	$	18,641