Fair Value Measurements (Tables)

12 Months Ended

Dec. 31, 2019

Fair Value Disclosures [Abstract]

Summary of Fair Value Assets Measured on Recurring Basis

All investments have been classified as “available-for-sale” and are carried at fair value based upon quoted market prices or pricing models for similar securities at period end. Generally, those investments with contractual maturities greater than 12 months are considered long-term investments.  Unrealized gains and losses, deemed temporary in nature, are reported as a component of accumulated other comprehensive loss, net of tax, on the consolidated balance sheets.

A decline in the fair value of any security below cost that is deemed other than temporary results in a charge to earnings and the corresponding establishment of a new cost basis for the security. The amortized cost of securities is adjusted for amortization of premiums and accretion of discounts to maturity. Dividend and interest income are recognized when earned. Realized gains and losses are included in earnings and are derived using the specific identification method for determining the cost of securities sold.

The following table sets forth the Company’s financial instruments that were measured at fair value on a recurring basis by level within the fair value hierarchy (in thousands):

	Fair Value Measurements at December 31, 2019
	Total		Level 1		Level 2		Level 3
Assets
Money market funds	$	100,441	$	100,441	$	—	$	—
U.S. government agency obligations		134,055		—		134,055		—
Corporate securities		194,789		—		194,789		—
Total	$	429,285	$	100,441	$	328,844	$	—
	Fair Value Measurements at December 31, 2018
	Total		Level 1		Level 2		Level 3
Assets
Money market funds	$	245,194	$	245,194	$	—	$	—
U.S. government agency obligations		85,033		—		85,033		—
Corporate securities		63,679		—		63,679		—
Total	$	393,906	$	245,194	$	148,712	$	—

Summary of Fair Value Measurement of Available-for-sale Securities

The following table is a summary of amortized cost, unrealized gain and loss, and fair value (in thousands) of the Company’s marketable securities by contractual maturities:

	Fair Value Measurements at December 31, 2019
	Amortized Cost		Unrealized Gain		Unrealized Loss			Fair Value
Cash equivalents (due within 90 days)	$	100,440	$	1	$	—		$	100,441
Short-term investments (due within one year)		314,181		523		(13	)		314,691
Long-term investments (due between one and two years)		14,110		47		(4	)		14,153
Total	$	428,731	$	571	$	(17	)	$	429,285
	Fair Value Measurements at December 31, 2018
	Amortized Cost		Unrealized Gain		Unrealized Loss			Fair Value
Cash equivalents (due within 90 days)	$	245,194	$	—	$	—		$	245,194
Short-term investments (due within one year)		68,656		—		(92	)		68,564
Long-term investments (due between one and two years)		80,118		98		(68	)		80,148
Total	$	393,968	$	98	$	(160	)	$	393,906