Fair Value Measurements (Tables)

6 Months Ended

Jun. 30, 2017

Fair Value Measurements [Abstract]

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

	Assets and Liabilities at Fair Value as of June 30, 2017
	Level 1		Level 2		Level 3		Total
	(in thousands)
Assets
Cash and cash equivalents	$	30,706	$	—	$	—	$	30,706
Short-term investments	160,842		39,639		—		200,481
Total cash and cash equivalents and investments	$	191,548	$	39,639	$	—	$	231,187

	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 June 30, 2017	$	—
Balance at December 31, 2015	$	22,815
Change in valuation of purchase consideration payable to former Symphony Icon stockholders	1,443
Balance at June 30, 2016	$	24,258