Fair Value Measurements (Tables)

3 Months Ended

Mar. 31, 2017

Fair Value Measurements [Abstract]

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

	Assets and Liabilities at Fair Value as of March 31, 2017
	Level 1		Level 2		Level 3		Total
	(in thousands)
Assets
Cash and cash equivalents	$	2,455	$	—	$	—	$	2,455
Short-term investments	191,248		66,040		—		257,288
Total cash and cash equivalents and investments	$	193,703	$	66,040	$	—	$	259,743

	Assets and Liabilities at Fair Value as of December 31, 2016
	Level 1		Level 2		Level 3		Total
	(in thousands)
Assets
Cash and cash equivalents	$	45,093	$	1,507	$	—	$	46,600
Short-term investments	227,805		72,099		—		299,904
Total cash and cash equivalents and investments	$	272,898	$	73,606	$	—	$	346,504
Liabilities
Accrued liabilities	$	—	$	—	$	18,912	$	18,912
Total liabilities	$	—	$	—	$	18,912	$	18,912

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

Balance at December 31, 2016	$	18,912
Change in valuation of purchase consideration payable to former Symphony Icon stockholders	2,101
Payment of contingent payment obligation with common stock and cash	(21,013		)
Balance at March 31, 2017	$	—
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