Marketable Securities (Tables)

3 Months Ended

Mar. 31, 2019

Investments Debt And Equity Securities [Abstract]

Summary of Cash Equivalents and Available-for-Sale Securities

The table below summarizes the Company’s cash equivalents and available-for-sale securities (in thousands):

			Gross		Gross
	Amortized		Unrealized		Unrealized			Estimated
	Cost		Gains		(Losses)			Fair Value
March 31, 2019
Assets
Cash equivalents:
Money market funds	$	15,233	$	—	$	—		$	15,233
Commercial paper securities		4,990		—		—			4,990
Total		20,223		—		—			20,223
Available-for-sale securities:
Commercial paper securities		180,380		19		—			180,399
Corporate debt securities		70,973		—		(25	)		70,948
U.S. government-sponsored entity debt securities		18,681		—		—			18,681
Total		270,034		19		(25	)		270,028
Total cash equivalents and available-for-sale securities	$	290,257	$	19	$	(25	)	$	290,251
December 31, 2018
Cash equivalents:
Money market funds	$	103,291	$	—	$	—		$	103,291
Total		103,291		—		—			103,291
Available-for-sale securities:
Commercial paper securities		177,353		—		(129	)		177,224
Corporate debt securities		63,981		—		(111	)		63,870
U.S. government-sponsored entity debt securities		18,640		—		(19	)		18,621
Total		259,974		—		(259	)		259,715
Total cash equivalents and available-for-sale securities	$	363,265		—	$	(259	)	$	363,006