Fair Value Measurements (Tables)

12 Months Ended

Dec. 31, 2015

Fair Value Measurements

Assets and liabilities measured at fair value on a recurring basis

Assets and liabilities measured at fair value on a recurring basis as of December 31, 2014 are as follows (in thousands):

			Quoted Prices		Significant
			in Active		Other		Significant
			Markets for		Observable		Unobservable
	December 31,		Identical Assets		Inputs		Inputs
Liabilities	2014		(Level 1)		(Level 2)		(Level 3)
Convertible preferred stock tranche liability	$	6,305	$	—	$	—	$	6,305
Total	$	6,305	$	—	$	—	$	6,305

Assets and liabilities measured at fair value on a recurring basis as of December 31, 2015 are as follows (in thousands):

			Quoted Prices		Significant
			in Active		Other		Significant
			Markets for		Observable		Unobservable
	December 31,		Identical Assets		Inputs		Inputs
Assets	2015		(Level 1)		(Level 2)		(Level 3)
	(unaudited)
Money market funds included in cash and cash equivalents	$	65,371	$	65,371	$	—	$	—
Marketable securities:
U.S. Treasury notes		50,175		50,152		—		—
U.S. government agency securities		43,885		—		43,870		—
Total	$	159,431	$	115,523	$	43,870	$	—

Assets and liabilities measured at fair value using Level 3 significant unobservable inputs

The following table provides a reconciliation of all assets and liabilities measured at fair value using Level 3 significant unobservable inputs (in thousands):

	Preferred Stock
	Tranche Liability
	(in thousands)
Balance at December 31, 2014	$	6,305
Changes in fair value		9,750
Reclassification to Series A Preferred Stock		(16,055)
Balance at December 31, 2015	$	—