Fair Value of Financial Assets and Liabilities

3 Months Ended

Mar. 31, 2020

Fair Value of Financial Assets and Liabilities

Fair Value of Financial Assets and Liabilities

3.           Fair Value of Financial Assets and Liabilities

Short-term investments as of March 31, 2020 and December 31, 2019 consisted of U.S. Treasury notes which investments were each due within six months of such date. As of March 31, 2020 and December 31, 2019, the fair value of short-term investments was $97,870 and $186,452, respectively.  As of March 31, 2020, the amortized cost was $97,630 and gross unrealized gain was $240.  As of December 31, 2019, the amortized cost was $186,415 and gross unrealized gain was $37. 

The following tables present information about the Company’s financial instruments measured at fair value on a recurring basis and indicate the level of the fair value hierarchy used to determine such fair values:

	Fair Value Measurements
	as of March 31, 2020 Using:
	Level 1		Level 2		Level 3		Total
Assets:
Restricted cash — money market funds	$	210	$	—	$	—	$	210
Cash equivalents — money market funds		54,855		—		—		54,855
Cash equivalents — U.S. Treasury notes		—		42,047		—		42,047
Short-term investments — U.S. Treasury notes		—		97,870		—		97,870
	$	55,065	$	139,917	$	—	$	194,982

	Fair Value Measurements
	as of December 31, 2019 Using:
	Level 1		Level 2		Level 3		Total
Assets:
Restricted cash — money market funds	$	210	$	—	$	—	$	210
Cash equivalents — money market funds		25,207		—		—		25,207
Cash equivalents — U.S. Treasury notes		—		10,192		—		10,192
Short-term investments — U.S. Treasury notes		—		186,452		—		186,452
	$	25,417	$	196,644	$	—	$	222,061

As of March 31, 2019, the Company did not hold any securities that were in an unrealized loss position. As of December 31, 2019, the Company held seven securities that were in an unrealized loss position. The aggregate fair value of securities held by the Company in an unrealized loss position at December 31, 2019 was $43,107. These securities were held by the Company in an unrealized loss position for less than 12 months. The Company determined that there was no material change in the credit risk of these securities. As a result, the Company determined it did not hold any investments with an other-than-temporary impairment as of March 31, 2020 and December 31, 2019.

During the three months ended March 31, 2020 and the year ended December 31, 2019 there were no transfers between Level 1,  Level 2 and Level 3. The money market funds were valued using quoted prices in active markets, which represent a Level 1 measurement in the fair value hierarchy. The Company's cash equivalents and short-term investments as of March 31, 2020 and December 31, 2019 included U.S. Treasury notes, which are not traded on a daily basis and, therefore, represent a Level 2 measurement in the fair value hierarchy at each period end.