Investments and Fair Value of Financial Assets and Liabilities
 9 Months Ended
Sep. 30, 2019
Investments and Fair Value of Financial Assets and Liabilities  
Investments and Fair Value of Financial Assets and Liabilities

3. Investments and Fair Value of Financial Assets and Liabilities

Investments by security type consisted of the following (in thousands):

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

September 30, 2019

 

 

Amortized Cost

 

Gross
Unrealized
Gains

 

Gross
Unrealized
Losses

 

Fair Value

U.S. treasury bills and notes (due within one year)

 

$

201,045

 

$

165

 

$

(8)

 

$

201,202

U.S. government agency bonds (due within one year)

 

 

13,867

 

 

 9

 

 

 —

 

 

13,876

 

 

$

214,912

 

$

174

 

$

(8)

 

$

215,078

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

December 31, 2018

 

 

Amortized Cost

 

Gross
Unrealized
Gains

 

Gross
Unrealized
Losses

 

Fair Value

U.S. treasury notes (due within one year)

 

$

79,312

 

$

 —

 

$

(26)

 

$

79,286

U.S. government agency bonds (due within one year)

 

 

17,704

 

 

 —

 

 

(3)

 

 

17,701

 

 

$

97,016

 

$

 —

 

$

(29)

 

$

96,987

 

The following tables present the Company’s fair value hierarchy for its assets and liabilities, which are measured at fair value on a recurring basis (in thousands):

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Fair value measurements at September 30, 2019 using:

 

 

 

 

 

 

 

 

 

 

 

 

 

 

    

Level 1

    

Level 2

    

Level 3

    

Total

Assets:

 

 

  

 

 

  

 

 

  

 

 

  

Cash equivalents:

 

 

  

 

 

  

 

 

  

 

 

  

Money market funds

 

$

109,611

 

$

 —

 

$

 —

 

$

109,611

Investments:

 

 

 

 

 

 

 

 

 

 

 

  

U.S. government agency bonds

 

 

 —

 

 

13,876

 

 

 —

 

 

13,876

U.S. treasury bills and notes

 

 

 —

 

 

201,202

 

 

 —

 

 

201,202

 

 

$

109,611

 

$

215,078

 

$

 —

 

$

324,689

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Fair value measurements at December 31, 2018 using:

 

 

 

 

 

 

 

 

 

 

 

 

 

 

    

Level 1 

    

Level 2 

    

Level 3

    

Total 

Assets:

 

 

  

 

 

  

 

 

  

 

 

  

Cash equivalents:

 

 

  

 

 

  

 

 

  

 

 

  

Money market funds

 

$

282,160

 

$

 —

 

$

 —

 

$

282,160

U.S. treasury bills

 

 

 —

 

 

24,904

 

 

 —

 

 

24,904

Investments:

 

 

  

 

 

  

 

 

  

 

 

  

U.S. government agency bonds

 

 

 —

 

 

17,701

 

 

 —

 

 

17,701

U.S. treasury notes

 

 

 —

 

 

79,286

 

 

 —

 

 

79,286

 

 

$

282,160

 

$

121,891

 

$

 —

 

$

404,051

 

U.S. government money market funds were valued by the Company based on quoted market prices, which represent a Level 1 measurement within the fair value hierarchy. U.S. treasury notes and U.S. government agency bonds were valued by the Company using quoted prices in active markets for similar securities, which represent a Level 2 measurement within the fair value hierarchy. There have been no changes to the valuation methods during the nine months ended September 30, 2019. The Company evaluates transfers between levels at the end of each reporting period. There were no transfers between Level 1, Level 2 or Level 3 during the nine months ended September 30, 2019.