Income taxes (Tables)

12 Months Ended

Jul. 31, 2019

Income Tax Disclosure [Abstract]

Schedule of Components of Income Tax Expense (Benefit) [Table Text Block]

The benefit for income taxes for fiscal years ended July 31 is as follows:

	2019		2018		2017
Federal	$	—	$	1,097	$	—
State and local		—		—		—
Foreign		—		—		—
Deferred benefit		—		—		—
Benefit for income taxes	$	—	$	1,097	$	—

Schedule of Deferred Tax Assets and Liabilities [Table Text Block]

Deferred tax assets and liabilities arise from temporary differences between the tax basis of assets and liabilities and their reported amounts in the financial statements. The components of deferred tax assets (liabilities) as of July 31 are as follows:

	2019			2018
Deferred tax assets:
Federal tax carryforward losses	$	12,558		$	13,975
Provision for uncollectible accounts receivable		1,116			791
State and local tax carry forward losses		144			352
Accrued royalties		101			102
Stock compensation		769			575
Depreciation		682			581
Research and development and other tax credit carryforwards		1,350			1,286
Foreign tax carryforward losses		3,783			2,771
Intangibles and goodwill		1,479			1,811
Inventory		1,086			1,786
Accrued expenses		1,127			1,194
Other, net		82			58
Deferred tax assets		24,277			25,282
Prepaid expenses		(626	)		(772	)
Other, net		(124	)		(39	)
Deferred tax liabilities		(750	)		(811	)
Net deferred tax assets before valuation allowance		23,527			24,471
Less: valuation allowance		(23,527	)		(24,471	)
Net deferred tax liabilities	$	—		$	—

Schedule of Income before Income Tax, Domestic and Foreign [Table Text Block]

The components of income (loss) before income taxes consisted of the following for the years ended July 31:

	2019			2018			2017
United States operations	$	4,618		$	(9,540	)	$	(212	)
International operations		(2,129	)		(1,878	)		(2,292	)
Income (loss) before taxes	$	2,489		$	(11,418	)	$	(2,504	)

Schedule of Effective Income Tax Rate Reconciliation [Table Text Block]

The benefit for income taxes was at rates different from U.S. federal statutory rates for the following reasons for the years ended July 31:

	2019			2018			2017
Federal statutory rate		(21.0	)%		26.4	%		34.0	%
Compensation and other expenses not deductible for income tax return purposes		(15.3	)		(1.0	)		(14.5	)
Change in valuation allowance		36.3			73.9			64.0
State tax law change		—			—			(81.1	)
Impact of Tax Act on valuation allowance		—			(100.1	)		—
AMT refund under Tax Act		—			9.6			—
Other		—			0.8			(2.4	)
		—	%		9.6	%		—	%