Summary of Significant Accounting Policies (Tables)

9 Months Ended

Sep. 30, 2018

Accounting Policies [Abstract]

Summary of Assets Measured at Fair Value on Recurring Basis

The following table summarizes assets measured at fair value on a recurring basis at September 30, 2018 (in thousands):

			Active		Observable		Unobservable
	September 30,		Markets		Inputs		Inputs
Description	2018		(Level 1)		(Level 2)		(Level 3)
Money market funds (included in    cash and cash equivalents)	$	14,791	$	14,791	$	—	$	—
U.S. treasury securities (included in    cash and cash equivalents)		8,065		8,065		—		—
U.S. treasury securities (included in    marketable securities)		92,522		92,522		—		—
Total	$	115,378	$	115,378	$	—	$	—

The following table summarizes assets measured at fair value on a recurring basis at December 31, 2017 (in thousands):

			Active		Observable		Unobservable
	December 31,		Markets		Inputs		Inputs
Description	2017		(Level 1)		(Level 2)		(Level 3)
Money market funds (included in    cash and cash equivalents)	$	53,349	$	53,349	$	—	$	—
Total	$	53,349	$	53,349	$	—	$	—

Schedule of Estimated Useful Lives of Property and Equipment

The estimated useful lives of property and equipment are as follows:

	Useful Life (in years)
Leasehold improvements	Lesser of useful life or remaining lease term
Laboratory and manufacturing equipment	2-8 years
Computer equipment	1-5 years
Furniture and fixtures	3-5 years
Office equipment	3-5 years
Software	3-5 years