5. FAIR VALUE OF FINANCIAL INSTRUMENTS (Tables)

6 Months Ended

Nov. 30, 2017

Fair Value Disclosures [Abstract]

Fair value by hierarchy

  The following table summarizes the Company’s financial assets measured at fair value on a recurring basis as of November 30, 2017 (in thousands):

	Balance as of
	November 30, 2017		Level 1		Level 2		Level 3
Money market funds	$	4,164	$	4,164	$	--	$	--
U.S. Treasury securities		9,962		9,962		--		--
Certificate of deposit		50		--		50		--
Assets	$	14,176	$	14,126	$	50	$	--

     The following table summarizes the Company’s financial assets measured at fair value on a recurring basis as of May 31, 2017 (in thousands):

	Balance as of
	May 31, 2017		Level 1		Level 2		Level 3
Money market funds	$	15,516	$	15,516	$	--	$	--
Certificate of deposit		50		--		50		--
Assets	$	15,566	$	15,516	$	50	$	--