Cash, Cash Equivalents and Investments (Tables)

6 Months Ended

Jun. 30, 2018

Cash and Cash Equivalents [Abstract]

Summary of Cash, Cash Equivalents and Held-to-Maturity Investments by Type

The following tables summarize the Company's cash, cash equivalents, and held-to-maturity investments at June 30, 2018 and December 31, 2017 (in thousands):

	As of June 30, 2018
	Amortized Cost		Gross Unrealized Losses			Fair Value		Cash and Cash Equivalents		Short-Term Investments
Cash	$	47,837	$	—		$	47,837	$	47,837	$	—
Level 1:
Money market funds	256,679		—			256,679		256,679		—
Corporate bonds	4,528		(3		)	4,525		1,000		3,528
Subtotal	261,207		(3		)	261,204		257,679		3,528
Level 2:
State and municipal obligations	2,587		—			2,587		1,991		596
Total	$	311,631	$	(3	)	$	311,628	$	307,507	$	4,124

	As of December 31, 2017
	Amortized Cost		Gross Unrealized Losses			Fair Value		Cash and Cash Equivalents		Short-Term Investments
Cash	$	53,459	$	—		$	53,459	$	53,459	$	—
Level 1:
Money market funds	20,884		—			20,884		20,884		—
Corporate bonds	6,632		(6		)	6,626		—		6,632
Subtotal	27,516		(6		)	27,510		20,884		6,632
Level 2:
State and municipal obligations	992		—			992		762		230
Total	$	81,967	$	(6	)	$	81,961	$	75,105	$	6,862