FAIR VALUE MEASUREMENTS

6 Months Ended

Jun. 30, 2020

The following tables present information about our assets that are measured at fair value on a recurring basis and indicate the fair value hierarchy of the valuation techniques we utilized to determine such fair value:


(In thousands)	As of June 30, 2020		Quoted Prices in Active Markets (Level 1)		Significant Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
Cash equivalents:
U.S. treasury securities	$	9,999	$	—	$	9,999	$	—
Money market funds	425,769		425,769		—		—
Marketable debt securities:
Commercial paper	11,613		—		11,613		—
Corporate notes	62,763		—		62,763		—
U.S. government-sponsored enterprise securities	244,071		—		244,071		—
U.S. treasury securities	939,978		—		939,978		—
Marketable equity securities	86,310		45,522		40,788		—
Restricted cash (money market funds)	1,483		1,483		—		—
Total	$	1,781,986	$	472,774	$	1,309,212	$	—


(In thousands)	As of December 31, 2019		Quoted Prices in Active Markets (Level 1)		Significant Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
Cash equivalents:
Commercial paper	$	3,439	$	—	$	3,439	$	—
U.S. treasury securities	336,693		—		336,693		—
Money market funds	119,882		119,882		—		—
Marketable debt securities:
Certificates of deposit	4,301		—		4,301		—
Commercial paper	36,474		—		36,474		—
Corporate notes	146,040		—		146,040		—
U.S. government-sponsored enterprise securities	32,488		—		32,488		—
U.S. treasury securities	755,714		—		755,714		—
Marketable equity securities	13,967		13,967		—		—
Restricted cash (money market funds)	1,482		1,482		—		—
Total	$	1,450,480	$	135,331	$	1,315,149	$	—

During the six months ended June 30, 2020 and 2019, there were no transfers between Level 1 and Level 2 financial assets. The carrying amounts reflected in our condensed consolidated balance sheets for cash, accounts receivable, net, other current assets, accounts payable and accrued expenses approximate fair value due to their short-term maturities.

In March 2020, pursuant to the Vir Agreement, we achieved a development milestone relating to ALN-HBV02 and earned a $15.0 million cash milestone and 1,111,111 shares of Vir's common stock, which were received in the second quarter of 2020. As a result of certain securities law restrictions, our Vir common stock is subject to a 180-day holding period. As such, we have recorded the investment at fair value, with the effect of the holding period restriction estimated using an option pricing valuation model, which is considered a Level 2 input. During the second quarter of 2020, we recognized an unrealized loss of $4.7 million to adjust our investment in Vir common stock to fair value as of June 30, 2020.

- Definition

The entire disclosure for the fair value of financial instruments (as defined), including financial assets and financial liabilities (collectively, as defined), and the measurements of those instruments as well as disclosures related to the fair value of non-financial assets and liabilities. Such disclosures about the financial instruments, assets, and liabilities would include: (1) the fair value of the required items together with their carrying amounts (as appropriate); (2) for items for which it is not practicable to estimate fair value, disclosure would include: (a) information pertinent to estimating fair value (including, carrying amount, effective interest rate, and maturity, and (b) the reasons why it is not practicable to estimate fair value; (3) significant concentrations of credit risk including: (a) information about the activity, region, or economic characteristics identifying a concentration, (b) the maximum amount of loss the entity is exposed to based on the gross fair value of the related item, (c) policy for requiring collateral or other security and information as to accessing such collateral or security, and (d) the nature and brief description of such collateral or security; (4) quantitative information about market risks and how such risks are managed; (5) for items measured on both a recurring and nonrecurring basis information regarding the inputs used to develop the fair value measurement; and (6) for items presented in the financial statement for which fair value measurement is elected: (a) information necessary to understand the reasons for the election, (b) discussion of the effect of fair value changes on earnings, (c) a description of [similar groups] items for which the election is made and the relation thereof to the balance sheet, the aggregate carrying value of items included in the balance sheet that are not eligible for the election; (7) all other required (as defined) and desired information.

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