Balance Sheet Details (Schedule of Patents) (Details) (USD $)	12 Months Ended
Jul. 31, 2014	Jul. 31, 2013	Oct. 31, 2014
Balance Sheet Details [Abstract]
Patents	$ 3,482,000pure_PatentsGross	$ 3,389,000pure_PatentsGross
Less accumulated amortization	(2,137,000)pure_AccumulatedAmortizationOnPatents	(1,959,000)pure_AccumulatedAmortizationOnPatents
Patents, net	1,345,000pure_PatentsNet	1,430,000pure_PatentsNet	1,305,000pure_PatentsNet
Impairment of patents		551,000us-gaap_AssetImpairmentCharges
Patent Amortization Expense	177,000us-gaap_AmortizationOfIntangibleAssets	188,000us-gaap_AmortizationOfIntangibleAssets
Weighted Average Remaining Amortization Period For Patents	8 years
Amortization expense, Next twelve months	183,000
Amortization expenses, Year two	183,000
Amortization expenses, Year three	183,000
Amortization expenses, Year four	183,000
Amortization expenses, Year five	$ 183,000

Accumulated Amortization On Patents

No definition available.

Name:	pure_AccumulatedAmortizationOnPatents
Namespace Prefix:	pure_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Finite Lived Intangible Assets Amortization Expense Rolling Average.

+ References

No definition available.

+ Details

Name:	pure_FiniteLivedIntangibleAssetsAmortizationExpenseRollingAverage
Namespace Prefix:	pure_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Patents, Gross

+ References

No definition available.

+ Details

Name:	pure_PatentsGross
Namespace Prefix:	pure_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Patents Net.

+ References

No definition available.

+ Details

Name:	pure_PatentsNet
Namespace Prefix:	pure_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

The aggregate expense charged against earnings to allocate the cost of intangible assets (nonphysical assets not used in production) in a systematic and rational manner to the periods expected to benefit from such assets. As a noncash expense, this element is added back to net income when calculating cash provided by or used in operations using the indirect method.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 28

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=31042434&loc=d3e3602-108585

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 350

-SubTopic 30

-Section 45

-Paragraph 2

-URI http://asc.fasb.org/extlink&oid=6388964&loc=d3e16225-109274

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 350

-SubTopic 30

-Section 50

-Paragraph 2

-Subparagraph (a)(2)

-URI http://asc.fasb.org/extlink&oid=26713463&loc=d3e16323-109275

+ Details

Name:	us-gaap_AmortizationOfIntangibleAssets
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amount of write-down of assets recognized in the income statement. Includes, but is not limited to, losses from tangible assets, intangible assets and goodwill.

+ References

+ Details

Name:	us-gaap_AssetImpairmentCharges
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Details

Name:	us-gaap_BalanceSheetRelatedDisclosuresAbstract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of amortization expense expected to be recognized during the next fiscal year following the latest fiscal year for assets, excluding financial assets and goodwill, lacking physical substance with a finite life.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 350

-SubTopic 30

-Section 50

-Paragraph 2

-Subparagraph (a)(3)

-URI http://asc.fasb.org/extlink&oid=26713463&loc=d3e16323-109275

+ Details

Name:	us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseNextTwelveMonths
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of amortization expense expected to be recognized during the fifth fiscal year following the latest fiscal year for assets, excluding financial assets and goodwill, lacking physical substance with a finite life.

+ References

+ Details

Name:	us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFive
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of amortization expense expected to be recognized during the fourth fiscal year following the latest fiscal year for assets, excluding financial assets and goodwill, lacking physical substance with a finite life.

+ References

+ Details

Name:	us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFour
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of amortization expense expected to be recognized during the third fiscal year following the latest fiscal year for assets, excluding financial assets and goodwill, lacking physical substance with a finite life.

+ References

+ Details

Name:	us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearThree
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of amortization expense expected to be recognized during the second fiscal year following the latest fiscal year for assets, excluding financial assets and goodwill, lacking physical substance with a finite life.

+ References

+ Details

Name:	us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearTwo
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant