FAIR VALUE MEASUREMENTS (Tables)

12 Months Ended

Dec. 31, 2018

Fair Value Disclosures [Abstract]

Fair Value Of Marketable Securities and Investments [Table Text Block]

The fair value hierarchy of the Company’s cash equivalents and marketable securities at December 31, 2018, and 2017, was as follows:

	Fair Value Measurement at
	December 31, 2018
(in thousands)	Total Fair Value		Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)
Corporate securities	$	94,451	$	—	$	94,451
Commercial paper	96,366		—		96,366
Money market funds	304		304		—
Total	$	191,121	$	304	$	190,817

	Fair Value Measurement at
	December 31, 2017
(in thousands)	Total Fair Value		Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)
Corporate securities	$	179,951	$	—	$	179,951
Commercial paper	51,122		—		51,122
Government securities	9,285		—		9,285
Money market funds	195		195		—
Total	$	240,553	$	195	$	240,358