Fair Value Measurements (Tables)

12 Months Ended

Dec. 31, 2018

Fair Value Disclosures [Abstract]

Summary of Financial Assets Measured at Fair Value on Recurring Basis

The following tables summarize the Company’s financial assets measured at fair value on a recurring basis as of December 31, 2018 and 2017 and by level within the fair value hierarchy:

Fair value measurement as of December 31, 2018:

			Quoted prices in		Significant other		Significant
Financial assets			active markets for		observable		unobservable
			identical assets		inputs		inputs
Type of Instrument	Total		(Level 1)		(Level 2)		(Level 3)
Cash and cash equivalents:
Money market funds and checking accounts	$	15,081	$	15,081	$	—	$	—
Available-for-sale marketable securities:
U.S. Treasury securities		19,539		—		19,539		—
U.S. government agency obligations		17,859		—		17,859		—
Corporate bonds		75,910		—		75,910		—
Commercial paper		50,390		—		50,390		—
Municipal bonds		4,000		—		4,000		—
Restricted cash:
Commercial money market account		769		769		—		—
Total financial assets	$	183,548	$	15,850	$	167,698	$	—

Fair value measurement as of December 31, 2017:

			Quoted pricesin		Significant other		Significant
Financial assets			active markets for		observable		unobservable
			identical assets		inputs		inputs
Type of Instrument	Total		(Level 1)		(Level 2)		(Level 3)
Cash and cash equivalents:
Money market fund and checking accounts	$	9,388	$	9,388	$	—	$	—
Available-for-sale marketable securities:
Money market fund		39,951		—		39,951		—
U.S. government agency obligations		7,794		—		7,794		—
Corporate bonds		15,907		—		15,907		—
Commercial paper		19,529		—		19,529		—
Restricted cash:
Commercial money market account		769		769		—		—
Total financial assets	$	93,338	$	10,157	$	83,181	$	—