Fair value measurements (Tables)

9 Months Ended

Sep. 30, 2019

Fair Value Disclosures [Abstract]

Schedule of Assets and Liabilities Measured at Fair Value on a Recurring Basis

The following tables summarize the assets measured at fair value on a recurring basis (in thousands):

	September 30, 2019
	Total		Level 1		Level 2
Assets
Cash and cash equivalents:
Cash	$	3,078	$	3,078	$	—
Money market funds	88,826		88,826		—
Total cash and cash equivalents	91,904		91,904		—
Short-term investments:
U.S. Treasury bills	32,954		32,954		—
Corporate debt securities	180,848		—		180,848
Commercial paper	110,985		—		110,985
U.S. Agency bonds	37,521		—		37,521
Total short-term investments	362,308		32,954		329,354
Total	$	454,212	$	124,858	$	329,354

	December 31, 2018
	Total		Level 1		Level 2
Assets
Cash and cash equivalents:
Cash	$	3,731	$	3,731	$	—
Money market funds	28,963		28,963		—
Total cash and cash equivalents	32,694		32,694		—
Short-term investments:
U.S. Treasury bills	3,771		3,771		—
Corporate debt securities	111,916		—		111,916
Commercial paper	74,409		—		74,409
Total short-term investments	190,096		3,771		186,325
Total	$	222,790	$	36,465	$	186,325