Cash and Cash Equivalents and Investments (Tables)

6 Months Ended

Jun. 30, 2020

Cash and Cash Equivalents and Investments [Abstract]

Schedule of Cash, Cash Equivalents and Short-term Investments [Table Text Block]

	As of June 30, 2020
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Estimated Fair Value
	(in thousands)
Cash and cash equivalents	$	86,943	$	—	$	—	$	86,943
Securities maturing within one year:
U.S. treasury securities	110,503		312		—		110,815
Corporate debt securities	4,108		—		—		4,108
Total short-term investments	$	114,611	$	312	$	—	$	114,923
Total cash and cash equivalents and investments	$	201,554	$	312	$	—	$	201,866
	As of December 31, 2019
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Estimated Fair Value
			(in thousands)
Cash and cash equivalents	$	36,112	$	—	$	—	$	36,112
Securities maturing within one year:
U.S. treasury securities	235,463		94		(10)		235,547
Total short-term investments	$	235,463	$	94	$	(10)	$	235,547
Total cash and cash equivalents and investments	$	271,575	$	94	$	(10)	$	271,659