Common Stock	12 Months Ended
Apr. 30, 2016
Equity [Abstract]
Common Stock	Common Stock On December1, 2014, the Company entered into note purchase agreements with and issued convertible promissory notes in the principal amount of $1 million each to Joel Ackerman, the Company’s Chief Executive Officer, and Dr. Ronnie Morris, the Company’s President, to finance the operations of the Company. The transaction was approved by the Company’s audit committee. The notes bore interest at 12% per annum and had an initial term of 90 days. The notes, including any accrued but unpaid interest, were convertible at the option of each noteholder: (a) upon the closing of any equity financing that occurred during the term of the notes, into the securities offered in the financing to other investors at a 5% discount to the price per share paid by other investors in the financing; and (b) upon the maturity date of the notes, into the Company’s common stock at the volume weighted average closing price of the common stock for the five trading days prior to such conversion. On February 28, 2015, the Company entered into amendments to the convertible promissory notes issued on December 1, 2014. The amendments extended the maturity dates of the convertible promissory notes to April 1, 2015. The amendments were approved by the Company’s audit committee. On March 11, 2015, the convertible promissory notes and accrued interest of $60,000 were converted into equity at a 5% discount as part of the 2015 Securities Purchase Agreement. The 5% discount was contingent up until the closing of the 2015 Securities Purchase Agreement at which time the 5% discount was converted to an amount of $100,000 and classified into equity along with the $60,000 accrued interest noted above. On March 11, 2015, the Company entered into a Securities Purchase Agreement (the "2015 Securities Purchase Agreement") with Battery Ventures IX, L.P. and Battery Investment Partners IX, LLC (collectively, "Battery"), New Enterprise Associates 14, Limited Partnership ("NEA"), Joel Ackerman, Chief Executive Officer and a director of the Company ("Ackerman"), Dr. Ronnie Morris, President and a director of the Company ("Morris"), Daniel Mendelson, a director of the Company ("Mendelson") and certain other investors (collectively with Battery, NEA, Ackerman, Morris and Mendelson, the "Investors"), for the sale to the Investors of units, each unit consisting of one share of the Company's Common Stock, par value $0.001 per share (the "Common Stock") and a warrant to buy 0.55 shares of Common Stock at $5.76 per share (the "Warrants"), at a purchase price of $4.80 per unit, for an aggregate of $14 million. The Warrants expire five years after the closing date. Ackerman and Morris converted convertible promissory notes dated December 1, 2014 in the principal amounts of $1 million each, plus accrued interest, into the units at a 5% discount, pursuant to the terms of the convertible promissory notes. The Company has accounted for the Common Stock for the March 2015 Private Placement as equity on the accompanying consolidated balance sheets for 2015. The amount allocated to common stock was $8.0 million. This allocation is equal to the total proceeds of $14 million less the amount allocated to warrants of $5.1 million and is also net of the direct and incremental costs associated with the 2015 Private Placement of $0.88 million. The Black Scholes pricing model was used to calculate the value of warrants relating to the 2015 Securities Purchase Agreement. The Investors have the right to require the Company to repurchase the purchased shares (the "Put Option") for cash for $4.80 per share upon a change of control or sale or exclusive license of substantially all of the Company's assets only if approved by the Company's board of directors. The Put Option will terminate upon the achievement of certain financial and other milestones. The Investors have certain participation rights with respect to future financings of the Company. The Company covenanted to register the resale of the shares of Common Stock to be issued to the Investors and the shares of Common Stock issuable upon exercise of the Warrants pursuant to a 2015 Amended and Restated Registration Rights Agreement, to pay certain liquidated damages if the Company fails to file such registration statement by a certain deadline, and to have it declared effective by a certain deadline or keep it effective for a certain period of time. The Company has not accrued any liquidated damages associated with the Amended and Restated Registration Right Agreement as the Company has filed the required registration statement and anticipates continued compliance with the agreement. The issuance of the shares of Common Stock resulted in the Company issuing an additional 188,704 shares of Common Stock to investors who purchased shares of Common Stock pursuant to a Securities Purchase Agreement dated as of March 24, 2011 (the "2011 Securities Purchase Agreement") due to contractual antidilution provisions in that 2011 Securities Purchase Agreement. The Company also amended and restated the 2011 Securities Purchase Agreement to eliminate these antidilution provisions going forward, and conform aspects of the put option in that 2011 Securities Purchase Agreement to terms of the Put Option in the 2015 Securities Purchase Agreement. The Company also issued an additional 131,945 warrants to its investors under the antidilution provision of 2011 Warrant Agreements under the Securities Purchase Agreement. Concurrently its investors agreed on certain amendments of the warrants to eliminate the antidilution rights for future transactions, by extending the term of the warrants by one year, and adjusting the exercise price to $4.80 as an incentive to remove the antidilution rights. This resulted in a modification charge of $413,521. The Company and its investors have amended and restated its Securities Purchase Agreement dated January 28, 2013 (the "2013 Securities Purchase Agreement") to conform aspects of the put option in that 2013 Securities Purchase Agreement to the Put Option in the 2015 Securities Purchase Agreement. The Company issued an additional 100,750 warrants to investors under the antidilution provision of 2013 Warrant Agreements under the Securities Purchase Agreement. Concurrently its investors agree on certain amendments of these warrants to eliminate the antidilution rights for future transactions, by extending the term of the warrant by one year and adjusting the exercise price to $4.80 as an incentive to remove the antidilution rights. This resulted in a modification charge of $172,344. On April 24, 2015, the Company filed an amendment to its Amended and Restated Certificate of Incorporation with the Secretary of State of the State of Delaware, which increased the total number of shares of common stock the Company is authorized to issue to 200,000,000 from 125,000,000. The Company had accounted for the warrants issued in connection with the April 2011 Private Placement and January 2013 Private Placement as a liability based on the exercise price reset provisions in each of the security agreements. This liability, which was recorded at fair value on the accompanying consolidated balance sheets, totaled $1.6 million at the time of the close of the March 2015 Private Placement Agreement. Due to the amendments noted above, the liability has been reclassified to equity as shown in note 2 above.

Common Stock

On December1, 2014, the Company entered into note purchase agreements with and issued convertible promissory notes in the principal amount of $1 million each to Joel Ackerman, the Company’s Chief Executive Officer, and Dr. Ronnie Morris, the Company’s President, to finance the operations of the Company. The transaction was approved by the Company’s audit committee.

The notes bore interest at 12% per annum and had an initial term of 90 days. The notes, including any accrued but unpaid interest, were convertible at the option of each noteholder: (a) upon the closing of any equity financing that occurred during the term of the notes, into the securities offered in the financing to other investors at a 5% discount to the price per share paid by other investors in the financing; and (b) upon the maturity date of the notes, into the Company’s common stock at the volume weighted average closing price of the common stock for the five trading days prior to such conversion.

On February 28, 2015, the Company entered into amendments to the convertible promissory notes issued on December 1, 2014. The amendments extended the maturity dates of the convertible promissory notes to April 1, 2015. The amendments were approved by the Company’s audit committee.

On March 11, 2015, the convertible promissory notes and accrued interest of $60,000 were converted into equity at a 5% discount as part of the 2015 Securities Purchase Agreement. The 5% discount was contingent up until the closing of the 2015 Securities Purchase Agreement at which time the 5% discount was converted to an amount of $100,000 and classified into equity along with the $60,000 accrued interest noted above.

On March 11, 2015, the Company entered into a Securities Purchase Agreement (the "2015 Securities Purchase Agreement") with Battery Ventures IX, L.P. and Battery Investment Partners IX, LLC (collectively, "Battery"), New Enterprise Associates 14, Limited Partnership ("NEA"), Joel Ackerman, Chief Executive Officer and a director of the Company ("Ackerman"), Dr. Ronnie Morris, President and a director of the Company ("Morris"), Daniel Mendelson, a director of the Company ("Mendelson") and certain other investors (collectively with Battery, NEA, Ackerman, Morris and Mendelson, the "Investors"), for the sale to the Investors of units, each unit consisting of one share of the Company's Common Stock, par value $0.001 per share (the "Common Stock") and a warrant to buy 0.55 shares of Common Stock at $5.76 per share (the "Warrants"), at a purchase price of $4.80 per unit, for an aggregate of $14 million. The Warrants expire five years after the closing date. Ackerman and Morris converted convertible promissory notes dated December 1, 2014 in the principal amounts of $1 million each, plus accrued interest, into the units at a 5% discount, pursuant to the terms of the convertible promissory notes.

The Company has accounted for the Common Stock for the March 2015 Private Placement as equity on the accompanying consolidated balance sheets for 2015. The amount allocated to common stock was $8.0 million. This allocation is equal to the total proceeds of $14 million less the amount allocated to warrants of $5.1 million and is also net of the direct and incremental costs associated with the 2015 Private Placement of $0.88 million. The Black Scholes pricing model was used to calculate the value of warrants relating to the 2015 Securities Purchase Agreement.

The Investors have the right to require the Company to repurchase the purchased shares (the "Put Option") for cash for $4.80 per share upon a change of control or sale or exclusive license of substantially all of the Company's assets only if approved by the Company's board of directors. The Put Option will terminate upon the achievement of certain financial and other milestones.

The Investors have certain participation rights with respect to future financings of the Company. The Company covenanted to register the resale of the shares of Common Stock to be issued to the Investors and the shares of Common Stock issuable upon exercise of the Warrants pursuant to a 2015 Amended and Restated Registration Rights Agreement, to pay certain liquidated damages if the Company fails to file such registration statement by a certain deadline, and to have it declared effective by a certain deadline or keep it effective for a certain period of time. The Company has not accrued any liquidated damages associated with the Amended and Restated Registration Right Agreement as the Company has filed the required registration statement and anticipates continued compliance with the agreement.

The issuance of the shares of Common Stock resulted in the Company issuing an additional 188,704 shares of Common Stock to investors who purchased shares of Common Stock pursuant to a Securities Purchase Agreement dated as of March 24, 2011 (the "2011 Securities Purchase Agreement") due to contractual antidilution provisions in that 2011 Securities Purchase Agreement. The Company also amended and restated the 2011 Securities Purchase Agreement to eliminate these antidilution provisions going forward, and conform aspects of the put option in that 2011 Securities Purchase Agreement to terms of the Put Option in the 2015 Securities Purchase Agreement. The Company also issued an additional 131,945 warrants to its investors under the antidilution provision of 2011 Warrant Agreements under the Securities Purchase Agreement. Concurrently its investors agreed on certain amendments of the warrants to eliminate the antidilution rights for future transactions, by extending the term of the warrants by one year, and adjusting the exercise price to $4.80 as an incentive to remove the antidilution rights. This resulted in a modification charge of $413,521.

The Company and its investors have amended and restated its Securities Purchase Agreement dated January 28, 2013 (the "2013 Securities Purchase Agreement") to conform aspects of the put option in that 2013 Securities Purchase Agreement to the Put Option in the 2015 Securities Purchase Agreement. The Company issued an additional 100,750 warrants to investors under the antidilution provision of 2013 Warrant Agreements under the Securities Purchase Agreement. Concurrently its investors agree on certain amendments of these warrants to eliminate the antidilution rights for future transactions, by extending the term of the warrant by one year and adjusting the exercise price to $4.80 as an incentive to remove the antidilution rights. This resulted in a modification charge of $172,344.

On April 24, 2015, the Company filed an amendment to its Amended and Restated Certificate of Incorporation with the Secretary of State of the State of Delaware, which increased the total number of shares of common stock the Company is authorized to issue to 200,000,000 from 125,000,000.

The Company had accounted for the warrants issued in connection with the April 2011 Private Placement and January 2013 Private Placement as a liability based on the exercise price reset provisions in each of the security agreements. This liability, which was recorded at fair value on the accompanying consolidated balance sheets, totaled $1.6 million at the time of the close of the March 2015 Private Placement Agreement. Due to the amendments noted above, the liability has been reclassified to equity as shown in note 2 above.