Fair Value Measurement (Tables)

3 Months Ended

Mar. 31, 2018

Fair Value Measurement [Abstract]

Schedule of assets and liabilities measured at fair value on a recurring basis

Assets and liabilities measured at fair value on a recurring basis consist of the following as of March 31, 2018 (in thousands):

			Fair Value Measurements at Reporting Date Using
			Quoted Prices in		Significant
			Active Markets		Other		Significant
			for Identical		Observable		Unobservable
	March 31,		Assets/Liabilities		Inputs		Inputs
	2018		(Level 1)		(Level 2)		(Level 3)
Assets:
Money market funds	$	101	$	101	$	—	$	—
Liabilities:
Deferred payments	$	4,556	$	—	$	—	$	4,556

Assets and liabilities measured at fair value on a recurring basis consist of the following as of December 31, 2017 (in thousands):

			Fair Value Measurements at Reporting Date Using
			Quoted Prices in		Significant
			Active Markets		Other		Significant
			for Identical		Observable		Unobservable
	December 31,		Assets/Liabilities		Inputs		Inputs
	2017		(Level 1)		(Level 2)		(Level 3)
Assets:
Money market funds	$	113	$	113	$	—	$	—
Liabilities:
Deferred payments	$	4,514	$	—	$	—	$	4,514

Schedule of changes in fair value of level 3 liability

	March 31, 2018
Balance as of the beginning of period	$	4,514
Amounts paid		(656)
Other adjustments to fair value		698
Balance at end of period	$	4,556