Fair Value Measurements (Tables)

3 Months Ended

Mar. 31, 2017

Fair Value Measurements

Schedule of financial assets and liabilities measured on a recurring basis

			Quoted Prices in
			Active Markets		Significant Other		Significant Other
			for Identical		Observable		Unobservable
			Assets		Inputs		Inputs
	Total		(Level 1)		(Level 2)		(Level 3)
	(in thousands)
Cash equivalents	$	43,939	$	43,939	$	—	$	—
Restricted short-term investments		1,519		1,519		—		—
Fair value measurement as of March 31, 2017	$	45,458	$	45,458	$	—	$	—
Cash equivalents	$	36,082	$	36,082	$	—	$	—
Restricted short-term investments		1,390		1,390		—		—
Fair value measurement as of December 31, 2016	$	37,472	$	37,472	$	—	$	—