Share-Based Payments (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
Apr. 30, 2013	Apr. 30, 2012
Stock-based compensation expense	$ 2,376	$ 3,323
General and Administrative Expense [Member]
Stock-based compensation expense	1,984	3,009
Selling and Marketing Expense [Member]
Stock-based compensation expense	263	240
Research and Development Expense [Member]
Stock-based compensation expense	37	39
Translational Oncology Solutions Cost of Sales [Member]
Stock-based compensation expense	20	10
Personalized Oncology Solutions Cost of Sales [Member]
Stock-based compensation expense	$ 72	$ 25

Represents the expense recognized during the period arising from equity-based compensation arrangements (for example, shares of stock, unit, stock options or other equity instruments) with employees, directors and certain consultants qualifying for treatment as employees.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 1

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5047-113901

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SAB TOPIC 14.F)

-URI http://asc.fasb.org/extlink&oid=27013229&loc=d3e301413-122809

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

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-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Staff Accounting Bulletin (SAB)

-Number Topic 14

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