Investments and Fair Value Measurements (Tables)

3 Months Ended

Mar. 31, 2020

Investments And Fair Value Measurements [Abstract]

Summary of Investments

The following is a summary of our investments at March 31, 2020 and December 31, 2019 (in thousands):

			Gross Unrealized					Estimated
March 31, 2020	Cost		Gains		Losses			Fair Value
Available-for-sale securities:
Corporate debt securities	$	112,967	$	14	$	(414	)	$	112,567
Debt securities issued by U.S. government agencies		85,776		558		—			86,334
Total securities with a maturity of one year or less	$	198,743	$	572	$	(414	)	$	198,901
Corporate debt securities	$	40,202	$	45	$	(175	)	$	40,072
Debt securities issued by U.S. government agencies		38,596		417		(4	)		39,009
Total securities with a maturity of one to two years		78,798		462		(179	)		79,081
Total available-for-sale securities	$	277,541	$	1,034	$	(593	)	$	277,982

			Gross Unrealized					Estimated
December 31, 2019	Cost		Gains		Losses			Fair Value
Available-for-sale securities:
Corporate debt securities	$	105,679	$	40	$	(23	)	$	105,696
Debt securities issued by U.S. government agencies		38,970		30		(6	)		38,994
Total securities with a maturity of one year or less	$	144,649	$	70	$	(29	)	$	144,690
Corporate debt securities	$	2,033	$	5	$	-		$	2,038
Debt securities issued by U.S. government agencies		14,079		—		(3	)		14,076
Total securities with a maturity of one to two years		16,112		5		(3	)		16,114
Total available-for-sale securities	$	160,761	$	75	$	(32	)	$	160,804

Assets Measured at Fair Value on a Recurring Basis

The following tables present the investments we held at March 31, 2020 and December 31, 2019 that are regularly measured and carried at fair value. The table segregates our investments by level within the fair value hierarchy of valuation techniques used to determine their fair value (in thousands):

	At March 31, 2020		Quoted Prices in Active Markets (Level 1)		Significant Other Observable Inputs (Level 2)
Money market funds (1)	$	119,699	$	119,699	$	—
Corporate debt securities (3)		152,639		—		152,639
Debt securities issued by U.S. government agencies (2)		125,343		—		125,343
Total	$	397,681	$	119,699	$	277,982

	At December 31, 2019		Quoted Prices in Active Markets (Level 1)		Significant Other Observable Inputs (Level 2)
Money market funds (1)	$	285,510	$	285,510	$	—
Corporate debt securities (2)		107,735		—		107,735
Debt securities issued by U.S. government agencies (3)		53,069		—		53,069
Total	$	446,314	$	285,510	$	160,804

(1) Included in cash and cash equivalents on our condensed consolidated balance sheet.

(2) At March 31, 2020 and December 31, 2019, $20.0 million and $4.0 million, respectively, was included in cash and cash equivalents on our condensed consolidated balance sheet, with the difference included in short-term investments on our condensed consolidated balance sheet.

(3) Included in short-term investments on our condensed consolidated balance sheet.