Income taxes (Tables)

12 Months Ended

Jul. 31, 2016

Income Tax Disclosure [Abstract]

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

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

	2016			2015			2014
Current (provision) benefit:
Federal	$	(968	)	$	—		$	—
State and local		(276	)		(72	)		(68	)
Foreign		(45	)		(25	)		(22	)
Deferred benefit		60			104			18
Benefit (provision) for income taxes	$	(1,229	)	$	7		$	(72	)

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

	2016			2015
Deferred tax assets:
Federal tax carryforward losses	$	18,964		$	35,411
Provision for uncollectible accounts receivable		1,406			685
State and local tax carry forward losses		2,757			2,661
Accrued royalties		146			144
Stock compensation		616			99
Depreciation		769			618
Research and development and other tax credit carryforwards		2,152			1,134
Foreign tax carryforward losses		2,046			1,476
Intangibles		2,915			2,951
Inventory		2,477			2,558
Accrued expenses		1,321			2,627
Unrealized foreign exchange		100			98
Other, net		63			18
Deferred tax assets		35,732			50,480
Deferred tax liabilities:
Deferred patent costs		—			(152	)
Prepaid expenses		(820	)		(676	)
Other, net		—			(31	)
Deferred tax liabilities		(820	)		(859	)
Net deferred tax assets before valuation allowance		34,912			49,621
Less: valuation allowance		(34,912	)		(49,658	)
Net deferred tax liabilities	$	—		$	(37	)

Schedule of Deferred Tax Liabilities Included In Consolidated Balance Sheets [Table Text Block]

Net deferred tax liabilities are included in the consolidated balance sheets as of July 31 as follows:

	2016		2015
Deferred taxes:
Current	$	—	$	—
Non-current		—		37
	$	—	$	37

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:

	2016			2015			2014
United States operations	$	48,847		$	(615	)	$	(8,702	)
International operations		(2,332	)		(1,677	)		(1,203	)
Income (loss) before taxes	$	46,515		$	(2,292	)	$	(9,905	)

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

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

	2016			2015			2014
Federal statutory rate		(34.0	)%		34.0	%		34.0	%
Penalties and other expenses not deductible for income tax return purposes		(1.1	)		(18.6	)		(6.6	)
State income taxes, net of benefit of federal tax deduction		(0.4	)		(0.5	)		0.2
Change in valuation allowance		32.9			(15.2	)		(16.5	)
State tax law change		—			—			(12.3	)
Other		—			0.6			0.5
		(2.6	)%		0.3	%		(0.7	)%