Fair Value Measurements (Tables)

9 Months Ended

Sep. 30, 2020

Fair Value Measurements [Abstract]

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

	Assets and Liabilities at Fair Value as of September 30, 2020
	Level 1		Level 2		Level 3		Total
	(in thousands)
Assets
Cash and cash equivalents	$	52,251	$	—	$	—	$	52,251
Short-term investments	38,836		20,359		—		59,195
Total cash and cash equivalents and investments	$	91,087	$	20,359	$	—	$	111,446

	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