Investments

9 Months Ended

Sep. 30, 2021

Investments, Debt and Equity Securities [Abstract]

The following tables summarize the Company’s short-term investments (in thousands):


		As of September 30, 2021
	Maturity	Amortized cost		Gross unrealized gains		Gross unrealized losses		Estimated fair value
Corporate debt securities	2 years or less	$	215,349	$	18	$	(41)	$	215,326
Commercial paper	1 year or less	528,373		81		(1)		528,453
U.S. Agency bonds	1 year or less	75,244		9		(1)		75,252
U.S. Treasury bills	2 years or less	83,723		22		(10)		83,735
Sovereign debt securities	1 year or less	9,030		—		(2)		9,028
		$	911,719	$	130	$	(55)	$	911,794


		As of December 31, 2020
	Maturity	Amortized cost		Gross unrealized gains		Gross unrealized losses		Estimated fair value
Corporate debt securities	2 years or less	$	130,814	$	160	$	(4)	$	130,970
Commercial paper	1 year or less	240,725		58		(18)		240,765
U.S. Agency bonds	2 years or less	83,227		37		(1)		83,263
U.S. Treasury bills	2 years or less	49,539		10		(3)		49,546
		$	504,305	$	265	$	(26)	$	504,544

The Company has classified all of its short-term investments as available-for-sale as the sale of such securities may be required prior to maturity to implement management strategies, and accordingly, carries these investments at fair value. As of September 30, 2021, and December 31, 2020, aggregated gross unrealized losses of available-for-sale investments were not material, and accordingly, no allowance for credit losses was recorded.

As of September 30, 2021 and December 31, 2020, the Company held 588,235 shares of ORIC Pharmaceuticals, Inc. (“ORIC”) common stock subject to certain transfer restrictions. The shares held by the Company are measured at fair value at each reporting period based on the closing price of ORIC’s common stock on the last trading day of each reporting period, adjusted for a discount for lack of marketability, with any unrealized gains and losses recorded in other income (expense), net on the Company’s condensed consolidated statements of operations and comprehensive loss. See Note 4 - Fair Value Measurements.