Fair Value Measurements and Marketable Securities (Tables)

3 Months Ended

Mar. 31, 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 March 31, 2018 Using:
	Level 1		Level 2		Level 3		Total
Assets:
Cash equivalents:
Money market funds	$	—	$	44,083	$	—	$	44,083
U.S. commercial paper		—		3,996		—		3,996
Total cash equivalents		—		48,079		—		48,079
Marketable securities:
U.S. government securities		—		8,919		—		8,919
U.S. corporate bonds		—		7,976		—		7,976
U.S. commercial paper		—		5,946		—		5,946
Total marketable securities		—		22,841		—		22,841
Total cash equivalents and marketable securities	$	—	$	70,920	$	—	$	70,920
Liabilities:
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
Liabilities:
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 March 31, 2018 (in thousands):

	March 31, 2018
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value
Assets:
U.S. government securities	$	8,925	$	—	$	(6	)	$	8,919
U.S. corporate bonds		7,999		—		(23	)		7,976
U.S. commercial paper		5,946		—		—			5,946
	$	22,870	$	—	$	(29	)	$	22,841