Fair Value Measurements Fair Value Measurements (Tables)

6 Months Ended

Jun. 30, 2017

Fair Value Disclosures [Abstract]

Fair Value, Assets Measured on Recurring and Nonrecurring Basis [Table Text Block]

The following table summarizes the levels of fair value measurements of our financial assets:

	Fair Value Measurements
	(in thousands)
	June 30, 2017		Level 1		Level 2		Level 3
Money market funds	$	230,227	$	230,227	$	—	$	—
Municipal bonds	1,929		—		1,929		—
Total	$	232,156	$	230,227	$	1,929	$	—

	Fair Value Measurements
	(in thousands)
	December 31, 2016		Level 1		Level 2		Level 3
Money market funds	$	283,322	$	283,322	$	—	$	—
Municipal bonds	1,851		—		1,851		—
Total	$	285,173	$	283,322	$	1,851	$	—