Fair Value Measurements - Hierarchy Levels (Details) - Recurring basis - USD ($)	Apr. 30, 2017	Jul. 31, 2016
Assets:
Total assets	$ 724,000	$ 740,000
Liabilities:
Total liabilities	1,138,000	1,579,000
Accrued expenses
Liabilities:
Assumed contingent obligation	12,000	12,000
Contingent guaranteed obligation		366,000
Total accrued expenses		378,000
Other long-term liabilities
Liabilities:
Assumed contingent obligation	1,126,000	1,126,000
Contingent guaranteed obligation		75,000
Total other long-term liabilities		1,201,000
Money markets | Cash and cash equivalents
Assets:
Money markets	724,000	740,000
Level 1
Assets:
Total assets	724,000	740,000
Level 1 | Money markets | Cash and cash equivalents
Assets:
Money markets	724,000	740,000
Level 3
Liabilities:
Total liabilities	1,138,000	1,579,000
Level 3 | Accrued expenses
Liabilities:
Assumed contingent obligation	12,000	12,000
Contingent guaranteed obligation		366,000
Total accrued expenses		378,000
Level 3 | Other long-term liabilities
Liabilities:
Assumed contingent obligation	$ 1,126,000	1,126,000
Contingent guaranteed obligation		75,000
Total other long-term liabilities		$ 1,201,000