Fair Value Measurements (Tables)

9 Months Ended

Sep. 30, 2019

Fair Value Disclosures [Abstract]

Summary of Financial Assets and Liabilities Measured at Fair Value on Recurring Basis

The following table summarizes the Company's financial assets and liabilities measured at fair value on a recurring basis at September 30, 2019 and December 31, 2018 by level within the fair value hierarchy. Financial assets and financial liabilities are classified in their entirety based on the lowest level of input that is significant to the fair value measurement (in thousands):

	As of September 30, 2019
	Quoted		Significant
	Prices in		Other		Significant
	Active		Observable		Unobservable
	Markets		Inputs		Inputs		Total Fair
	(Level 1)		(Level 2)		(Level 3)		Value
Assets:
Cash equivalents:
Money market funds	$	174,819	$	—	$	—	$	174,819
Total financial assets	$	174,819	$	—	$	—	$	174,819
Liabilities:
Contingent consideration	$	—	$	—	$	550	$	550
Total financial liabilities	$	—	$	—	$	550	$	550
	As of December 31, 2018
	Quoted		Significant
	Prices in		Other		Significant
	Active		Observable		Unobservable
	Markets		Inputs		Inputs		Total Fair
	(Level 1)		(Level 2)		(Level 3)		Value
Assets:
Cash equivalents:
Money market funds	$	47,258	$	—	$	—	$	47,258
U.S. government and agency securities		—		2,272		—		2,272
Short-term investments:
U.S. treasury securities		—		38,809		—		38,809
U.S. government and agency securities		—		6,732		—		6,732
Total financial assets	$	47,258	$	47,813	$	—	$	95,071

Summary of Changes in Level 3 Financial Instruments

The following table summarizes the changes in Level 3 financial instruments (in thousands):

Fair Value at December 31, 2018	$	—
Additions from acquisition		550
Balance at September 30, 2019	$	550