Fair Value Measurements (Tables)

12 Months Ended

Dec. 31, 2019

Fair Value Disclosures [Abstract]

Schedule of Assets Measured at Fair Value on Recurring Basis

Assets measured at fair value on a recurring basis were as follows:

Description	December 31, 2019		Quoted Prices (Unadjusted) in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
	(in thousands)
Cash equivalents:
Money market mutual funds	$	39,524	$	39,524	$	—	$	—
Repurchase agreements		14,000		—		14,000		—
Total cash equivalents	$	53,524	$	39,524	$	14,000	$	—
Short-term investments:
Asset-backed securities	$	14,876	$	—	$	14,876	$	—
Commercial paper		41,259		—		41,259		—
U.S. Treasury securities		59,971		—		59,971		—
Corporate debt securities		92,508		—		92,508		—
Total short-term investments	$	208,614	$	—	$	208,614	$	—
Total financial assets	$	262,138	$	39,524	$	222,614	$	—

Description	December 31, 2018		Quoted Prices (Unadjusted) in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
	(in thousands)
Cash equivalents:
Money market mutual funds	$	31,740	$	31,740	$	—	$	—
Commercial paper		5,974		—		5,974		—
U.S. Treasury securities		35		35		—		—
Total cash equivalents	$	37,749	$	31,775	$	5,974	$	—
Short-term investments:
Asset-backed securities	$	19,520	$	—	$	19,520	$	—
U.S. Treasury securities		29,939		—		29,939		—
Corporate debt securities		54,461		—		54,461		—
Commercial paper		72,597		—		72,597		—
Total short-term investments	$	176,517	$	—	$	176,517	$	—
Total financial assets	$	214,266	$	31,775	$	182,491	$	—