Fair Value Measurements (Tables)

3 Months Ended

Mar. 31, 2020

Fair Value Disclosures [Abstract]

Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis

We measure cash, cash equivalents and short-term investments at fair value on a recurring basis. The fair values of such assets were as follows (in thousands):

			Fair Value Measurements at Reporting Date Using
	Balance at March 31, 2020		Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
Cash and money market funds	$	103,285	$	103,285	$	—	$	—
U.S. treasury bills and government agency obligations		101,431		101,431		—		—
U.S. corporate debt securities		69,938		—		69,938		—
Foreign corporate debt securities		25,493		—		25,493		—
U.S. commercial paper		25,873		—		25,873		—
Foreign commercial paper		30,326		—		30,326		—
Total	$	356,346	$	204,716	$	151,630	$	—

			Fair Value Measurements at Reporting Date Using
	Balance at December 31, 2019		Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
Cash and money market funds	$	56,931	$	56,931	$	—	$	—
U.S. treasury bills and government agency obligations		140,626		140,626		—		—
U.S. corporate debt securities		80,170		—		80,170		—
Foreign corporate debt securities		23,203		—		23,203		—
U.S. commercial paper		32,801		—		32,801		—
Foreign commercial paper		57,241		—		57,241		—
Total	$	390,972	$	197,557	$	193,415	$	—