Investments and Fair Value Measurements (Tables)

6 Months Ended

Jun. 30, 2020

Investments And Fair Value Measurements [Abstract]

Summary of Investments

The following is a summary of our investments at June 30, 2020 and December 31, 2019 (in thousands):

			Gross Unrealized					Estimated
June 30, 2020	Cost		Gains		Losses			Fair Value
Available-for-sale securities:
Corporate debt securities	$	81,143	$	374	$	(1	)	$	81,516
Debt securities issued by U.S. government agencies		118,414		489		(5	)		118,898
Total securities with a maturity of one year or less	$	199,557	$	863	$	(6	)	$	200,414
Corporate debt securities	$	30,878	$	354	$	-		$	31,232
Debt securities issued by U.S. government agencies		22,272		230		(4	)		22,498
Total securities with a maturity of one to two years		53,150		584		(4	)		53,730
Total available-for-sale securities	$	252,707	$	1,447	$	(10	)	$	254,144

			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 June 30, 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 June 30, 2020		Quoted Prices in Active Markets (Level 1)		Significant Other Observable Inputs (Level 2)
Money market funds (1)	$	105,972	$	105,972	$	—
Corporate debt securities (3)		112,749		—		112,749
Debt securities issued by U.S. government agencies (3)		141,395		—		141,395
Total	$	360,116	$	105,972	$	254,144

	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 December 31, 2019, $4.0 million 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.