Segment reporting (Details) - Schedule of segment revenue by geographical (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Jul. 31, 2014	Jul. 31, 2013	Jul. 31, 2012
Segment reporting (Details) - Schedule of segment revenue by geographical [Line Items]
Sales Revenue Net	$ 95,947	$ 93,707	$ 103,083
Life Sciences [Member] | UNITED STATES
Segment reporting (Details) - Schedule of segment revenue by geographical [Line Items]
Sales Revenue Net	25,700	24,669	28,372
Life Sciences [Member] | Foreign Countries [Member]
Segment reporting (Details) - Schedule of segment revenue by geographical [Line Items]
Sales Revenue Net	11,558	13,149	15,308
Life Sciences [Member]
Segment reporting (Details) - Schedule of segment revenue by geographical [Line Items]
Sales Revenue Net	37,258	37,818	43,680
UNITED STATES
Segment reporting (Details) - Schedule of segment revenue by geographical [Line Items]
Sales Revenue Net	$ 84,389	$ 80,559	$ 87,776