Fair Value Measurements (Tables)

12 Months Ended

Dec. 31, 2016

Fair Value Measurements [Abstract]

Fair Value Hierarchy

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

	Fair Value at December 31, 2016						Fair Value at December 31, 2015
	Level 1		Level 2		Level 3		Level 1		Level 2		Level 3
Assets
Money market funds	$	95,896	$	—	$	—	$	14,950	$	—	$	—
Government-backed securities		—		19,000		—		—		20,000		—
Asset-backed securities(1)		—		23,632		—		—		28,924		—
Corporate debt securities(2)		—		79,470		—		—		137,213		—
Total cash equivalents and marketable securities	$	95,896	$	122,102	$	—	$	14,950	$	186,137	$	—
Liabilities
Convertible notes payable	$	—	$	141,989	$	—	$	—	$	—	$	—

(1) Includes $8,185 classified as cash and cash equivalents as of December 31, 2015 (see Note 3).

(2) Includes $11,976 and $20,404 classified as cash and cash equivalents as of December 31, 2016 and 2015, respectively (see Note 3).