Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	9 Months Ended
	Feb. 28, 2018		Feb. 28, 2017
Cash flows from operating activities:
Net income (loss)	$ 337		$ (4,858)
Adjustments to reconcile net income (loss) to net cash used in operating activities:
Stock-based compensation expense	822		791
(Recovery of) provision for doubtful accounts	(3)		16
Amortization of debt issuance costs	0		133
Depreciation and amortization	300		195
Accretion of investment discount	(24)		0
Changes in operating assets and liabilities:
Accounts receivable	(527)		(1,119)
Inventories	(2,392)		197
Prepaid expenses and other assets	(603)		(100)
Accounts payable	(268)		726
Accrued expenses	31		325
Customer deposits and deferred revenue	(764)		(797)
Income taxes payable	(5)		23
Net cash used in operating activities	(3,096)		(4,468)
Cash flows from investing activities:
Purchase of investments	(5,965)		0
Purchases of property and equipment	(458)		(219)
Net cash used in investing activities	(6,423)		(219)
Cash flows from financing activities:
Proceeds from issuance of common stock under private placement, net of issuance costs	0		5,299
Proceeds from issuance of common stock under employee plans, net of taxes paid related to share settlement of equity awards	727		510
Net cash provided by financing activities	727		5,809
Effect of exchange rates on cash and cash equivalents	66		(22)
Net (decrease) increase in cash and cash equivalents	(8,726)		1,100
Cash and cash equivalents, beginning of period	17,803	[1]	939
Cash and cash equivalents, end of period	9,077		2,039
Supplemental disclosure of non-cash flow information:
Fair value of common stock issued to settle accounts payable	0		323
Transfer of property and equipment to inventories	$ 372		$ 372

[1] The condensed consolidated balance sheet at May 31, 2017 has been derived from the audited consolidated financial statements at that date.