Fair Value Measurements (Tables)

9 Months Ended

Sep. 30, 2017

Fair Value Disclosures [Abstract]

Schedule of fair value hierarchy for the Company’s financial assets and liabilities which require fair value measurement on a recurring basis

The following table represents the fair value hierarchy for the Company’s financial assets and liabilities which require fair value measurement on a recurring basis (in thousands):

	September 30, 2017
	Total		Level 1		Level 2		Level 3
Assets:
Money market	$	11,043	$	11,043	$	—	$	—
Corporate debt	37,913		—		37,913		—
U.S. Treasury notes	70,696		—		70,696		—
Total assets measured at fair value	$	119,652	$	11,043	$	108,609	$	—
Liabilities:
Embedded derivative liability	$	233	$	—	$	—	$	233
Total liabilities measured at fair value	$	233	$	—	$	—	$	233

	December 31, 2016
	Total		Level 1		Level 2		Level 3
Assets:
Money market	$	192	$	192	$	—	$	—
Corporate debt	51,233		—		51,233		—
U.S. Treasury notes	60,976		—		60,976		—
Total assets measured at fair value	$	112,401	$	192	$	112,209	$	—

Summary of the changes in the estimated fair value of the Company’s embedded derivative

The following table sets forth a summary of the changes in the estimated fair value of the Company’s embedded derivative, which is measured at fair value as a Level 3 liability on a recurring basis (in thousands):

Balance as of December 31, 2016	$	—
Issuance of long-term debt with embedded derivative	764
Change in fair value included in interest and other income, net	(531		)
Balance as of September 30, 2017	$	233