Stock-Based Compensation (Details) (USD $)
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3 Months Ended | 9 Months Ended | 3 Months Ended | 9 Months Ended | 3 Months Ended | 9 Months Ended | 3 Months Ended | 9 Months Ended | 3 Months Ended | 9 Months Ended | 1 Months Ended | 3 Months Ended | 0 Months Ended | |||||||||||||||
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Apr. 30, 2013
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Apr. 30, 2012
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Apr. 30, 2013
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Apr. 30, 2012
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Apr. 30, 2013
Maximum
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Apr. 30, 2012
Maximum
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Apr. 30, 2013
Maximum
|
Apr. 30, 2012
Maximum
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Apr. 30, 2013
Minimum
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Apr. 30, 2012
Minimum
|
Apr. 30, 2013
Minimum
|
Apr. 30, 2012
Minimum
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Apr. 30, 2013
Research and development expense
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Apr. 30, 2013
Research and development expense
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Apr. 30, 2013
General and administrative expense
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Apr. 30, 2013
General and administrative expense
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May 31, 2011
2011 Plan
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May 31, 2011
2011 Plan
Maximum
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May 31, 2011
2011 Plan
Minimum
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Apr. 30, 2013
2011 Plan
Employees
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Oct. 31, 2012
2011 Plan
Employees
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Oct. 31, 2012
2011 Plan
Employees
Maximum
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Oct. 31, 2012
2011 Plan
Employees
Minimum
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Jan. 31, 2013
2011 Plan
Consultant
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Oct. 31, 2012
2011 Plan
Consultant
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Apr. 30, 2013
2011 Plan
Director
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Apr. 30, 2013
2011 Plan
Employees and directors
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Apr. 15, 2013
Amended 2011 Plan
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Stock-based compensation | ||||||||||||||||||||||||||||
Number of additional shares authorized | 5,200,000 | 3,800,000 | ||||||||||||||||||||||||||
Number of shares authorized | 9,000,000 | |||||||||||||||||||||||||||
Purchase price of incentive stock options as a percentage of its fair value | 100.00% | |||||||||||||||||||||||||||
Term of stock options | 10 years | 10 years | 10 years | 10 years | 3 years | 10 years | ||||||||||||||||||||||
Provisional percentage of outstanding stock owned by stockholders | 10.00% | |||||||||||||||||||||||||||
Exercise price as a percentage of fair value of common stock for stockholders who own more than 10% of outstanding stock | 110.00% | |||||||||||||||||||||||||||
Options granted to purchase shares | 2,200,000 | 155,000 | 30,000 | 1,200,000 | 815,000 | |||||||||||||||||||||||
Vesting period | 3 years | 3 years | 2 years | 1 year | 1 year | |||||||||||||||||||||||
Exercise price, high end of the range (in dollars per share) | $ 0.26 | $ 0.42 | ||||||||||||||||||||||||||
Exercise price, low end of the range (in dollars per share) | $ 0.23 | $ 0.20 | ||||||||||||||||||||||||||
Exercise price (in dollars per share) | $ 0.35 | $ 0.18 | $ 0.25 | |||||||||||||||||||||||||
Expected volatility, minimum (as a percent) | 81.92% | 85.96% | 81.92% | 85.96% | ||||||||||||||||||||||||
Expected volatility, maximum (as a percent) | 97.85% | 125.00% | 97.85% | 125.00% | ||||||||||||||||||||||||
Risk-free interest rate (as a percent) | 1.97% | 2.08% | 1.97% | 2.08% | 0.31% | 0.82% | 0.31% | 0.82% | ||||||||||||||||||||
Expected forfeiture rate (as a percent) | 0.00% | 0.00% | 0.00% | 0.00% | ||||||||||||||||||||||||
Expected term | 10 years | 10 years | 10 years | 10 years | 3 years | 5 years | 3 years | 5 years | ||||||||||||||||||||
Forfeiture rate (as a percent) | 0.00% | 0.00% | ||||||||||||||||||||||||||
Stock-based compensation expense recognized | $ 90,000 | $ 357,000 | $ 1,000 | $ 32,000 | $ 89,000 | $ 325,000 | ||||||||||||||||||||||
Option Shares Outstanding | ||||||||||||||||||||||||||||
Balance at the beginning of the period (in shares) | 3,175,000 | |||||||||||||||||||||||||||
Granted (in shares) | 2,200,000 | 155,000 | 30,000 | 1,200,000 | 815,000 | |||||||||||||||||||||||
Exercised (in shares) | (750,000) | |||||||||||||||||||||||||||
Forfeited/Cancelled (in shares) | (273,500) | |||||||||||||||||||||||||||
Balance at the end of the period (in shares) | 4,351,500 | 4,351,500 | ||||||||||||||||||||||||||
Weighted-Average Exercise Price | ||||||||||||||||||||||||||||
Balance at the beginning of the period (in dollars per share) | $ 0.24 | |||||||||||||||||||||||||||
Granted (in dollars per share) | $ 0.21 | |||||||||||||||||||||||||||
Exercised (in dollars per share) | $ 0.18 | |||||||||||||||||||||||||||
Forfeited/Cancelled (in dollars per share) | $ 0.33 | |||||||||||||||||||||||||||
Balance at the end of the period (in dollars per share) | $ 0.23 | $ 0.23 | ||||||||||||||||||||||||||
Aggregate Intrinsic Value | ||||||||||||||||||||||||||||
Balance at the beginning of the period (in dollars) | 24,000 | |||||||||||||||||||||||||||
Granted (in dollars) | 165,000 | |||||||||||||||||||||||||||
Exercised (in dollars) | 50,000 | |||||||||||||||||||||||||||
Balance at the end of the period (in dollars) | $ 275,000 | $ 275,000 |