Fair Value Measurements and Marketable Securities (Tables)

9 Months Ended

Sep. 30, 2018

Fair Value Disclosures [Abstract]

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

The following tables present information about the Company’s assets and liabilities that are measured at fair value on a recurring basis (in thousands):

	Fair Value Measurements at September 30, 2018 Using:
	Level 1		Level 2		Level 3		Total
Assets:
Cash equivalents:
Money market funds	$	—	$	29,896	$	—	$	29,896
U.S. government securities		—		5,994		—		5,994
Total cash equivalents		—		35,890		—		35,890
Marketable securities:
U.S. government securities		—		38,761		—		38,761
U.S. corporate bonds		—		35,594		—		35,594
U.S. commercial paper		—		16,390		—		16,390
Total marketable securities		—		90,745		—		90,745
Total cash equivalents and marketable securities	$	—	$	126,635	$	—	$	126,635
Derivative liabilities:
Anti-dilution rights	$	—	$	—	$	223	$	223
Total derivative liabilities	$	—	$	—	$	223	$	223

	Fair Value Measurements at December 31, 2017 Using:
	Level 1		Level 2		Level 3		Total
Assets:
Cash equivalents:
Money market funds	$	—	$	83,121	$	—	$	83,121
	$	—	$	83,121	$	—	$	83,121
Derivative liabilities:
Anti-dilution rights	$	—	$	—	$	223	$	223
	$	—	$	—	$	223	$	223

Summary of Gross Unrealized Gains and Losses of Marketable Securities

The following table summarizes the gross unrealized gains and losses of the Company’s marketable securities as of September 30, 2018 (in thousands):

	September 30, 2018
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value
Assets:
U.S. government securities	$	38,771	$	1	$	(11	)	$	38,761
U.S. corporate bonds		35,607		1		(14	)		35,594
U.S. commercial paper		16,390		—		—			16,390
	$	90,768	$	2	$	(25	)	$	90,745