Fair Value Measurements (Tables)

6 Months Ended

Jun. 30, 2020

Fair Value Measurements [Abstract]

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

	Assets and Liabilities at Fair Value as of June 30, 2020
	Level 1		Level 2		Level 3		Total
	(in thousands)
Assets
Cash and cash equivalents	$	86,943	$	—	$	—	$	86,943
Short-term investments	110,815		4,108		—		114,923
Total cash and cash equivalents and investments	$	197,758	$	4,108	$	—	$	201,866

	Assets and Liabilities at Fair Value as of December 31, 2019
	Level 1		Level 2		Level 3		Total
	(in thousands)
Assets
Cash and cash equivalents	$	36,112	$	—	$	—	$	36,112
Short-term investments	235,547		—		—		235,547
Total cash and cash equivalents and investments	$	271,659	$	—	$	—	$	271,659