Investments and Fair Value Measurements

12 Months Ended

Dec. 31, 2020

Investments and Fair Value Measurements

Investments and Fair Value Measurements

6. Investments and Fair Value Measurements

Available-for-Sale Securities

The estimated fair value of marketable securities is based on quoted market prices for these or similar investments obtained from a commercial pricing service. The fair market value of marketable securities classified within Level 1 is based on quoted prices for identical instruments in active markets. The fair value of marketable securities classified within Level 2 is based on quoted prices for similar instruments in active markets; quoted prices for identical or similar instruments in markets that are not active; or model-driven valuations whose inputs are observable or whose significant value drivers are observable. Observable inputs may include benchmark yields, reported trades, broker/dealer quotes, issuer spreads, two-sided markets, benchmark securities, bids, offers and reference data including market research publications.

Available-for-sale securities are summarized below:

		December 31, 2020
				Gross		Gross
		Amortized		Unrealized		Unrealized		Estimated
(In thousands)		Cost		Gains		Losses		Fair Value
US government securities	Level 1	$	75,036	$	34	$	—	$	75,070
US government agency securities	Level 2		74,971		18		—		74,989
Corporate notes	Level 2		5,046		—		(1)		5,045
Commercial paper	Level 2		56,374		1		(5)		56,370
Marketable securities			211,427		53		(6)		211,474
Money market funds	Level 1		—		—		—		—
Total		$	211,427	$	53	$	(6)	$	211,474

		December 31, 2019
				Gross		Gross
		Amortized		Unrealized		Unrealized		Estimated
(In thousands)		Cost		Gains		Losses		Fair Value
US government securities	Level 1	$	100,746	$	108	$	—	$	100,854
Corporate notes	Level 2		25,466		9		(1)		25,474
Commercial paper	Level 2		112,066		31		(2)		112,095
Marketable securities			238,278		148		(3)		238,423
Money market funds	Level 1		35,736		—		—		35,736
Total		$	274,014	$	148	$	(3)	$	274,159

As of December 31, 2020, all of the Company’s available-for-sale securities had contractual maturities within 8 months and the weighted-average maturity of marketable securities was approximately 3 months. There were no transfers between Level 1 and Level 2 during the periods presented, and there have been no material changes to the Company’s valuation techniques during the year ended December 31, 2020 or 2019.

Available-for-sale debt securities with unrealized losses are summarized below:

	December 31, 2020
	Less than 12 Months				Greater than 12 Months				Total
			Gross				Gross				Gross
	Estimated		Unrealized		Estimated		Unrealized		Estimated		Unrealized
(In thousands)	Fair Value		Losses		Fair Value		Losses		Fair Value		Losses
Corporate notes	$	5,045	$	(1)	$	—	$	—	$	5,045	$	(1)
Commercial paper		39,375		(5)		—		—		39,375		(5)
Total	$	44,420	$	(6)	$	—	$	—	$	44,420	$	(6)

	December 31, 2019
	Less than 12 Months				Greater than 12 Months				Total
			Gross				Gross				Gross
	Estimated		Unrealized		Estimated		Unrealized		Estimated		Unrealized
(In thousands)	Fair Value		Losses		Fair Value		Losses		Fair Value		Losses
Corporate notes	$	5,507	$	(1)	$	—	$	—	$	5,507	$	(1)
Commercial paper		28,137		(2)		—		—		28,137		(2)
Total	$	33,644	$	(3)	$	—	$	—	$	33,644	$	(3)

The Company invests primarily in high credit quality and short-term maturity debt securities with the intent to hold such securities until maturity at par value. The Company does not intend to sell the investments that are currently in an unrealized loss position, and it is unlikely that it will be required to sell the investments before recovery of their amortized cost basis, which may be maturity. The Company reviewed its available-for-sale debt securities and determined that there were no credit-related losses to be recognized as of December 31, 2020.

As of December 31, 2020, the Company’s accumulated other comprehensive income on its consolidated balance sheets consisted of net unrealized gains or losses on available-for-sale investments. For the year ended December 31, 2020, the Company sold marketable securities for total proceeds of $19.9 million and recognized minimal net realized gains from the sales based on the specific identification method. For the year ended December 31, 2019 and 2018, the Company did not sell any of its marketable securities.