Fair Value Measurements (Tables)

3 Months Ended

Mar. 31, 2015

Fair Value Measurements [Abstract]

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

	Assets and Liabilities at Fair Value as of March 31, 2015
	Level 1		Level 2		Level 3		Total
	(in thousands)
Assets
Cash and cash equivalents	$	41,960	$	—	$	—	$	41,960
Short-term investments	272,585		552		—		273,137
Total cash and cash equivalents and investments	$	314,545	$	552	$	—	$	315,097
Liabilities
Other long-term liabilities	$	—	$	—	$	18,641	$	18,641
Total liabilities	$	—	$	—	$	18,641	$	18,641

	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	1,753
Reclassification to accounts payable for payment due of contingent payment obligation with cash	(750		)
Balance at March 31, 2015	$	18,641
Balance at December 31, 2013	$	27,710
Change in valuation of purchase consideration payable to former Symphony Icon stockholders	1,142
Balance at March 31, 2014	$	28,852