Subsequent Events	12 Months Ended
Apr. 30, 2016
Subsequent Events [Abstract]
Subsequent Events	Subsequent Events On June 15, 2016, the Company closed a public offering of 2,000,000 registered shares of its common stock, par value $0.001 per share, at an offering price of $2.25 per share. In addition, the underwriter exercised a partial exercise of the over-allotment option granted to the underwriter to purchase an additional 258,749 shares of its common stock at the public offering price. All of the shares have been offered by the Company. The net proceeds from the offering, including the partial exercise of the over-allotment option, is approximately $4.3 million million, after deducting the underwriting discount and estimated offering-related expenses of $750,000. The Company intends to use the net proceeds of this offering for research and development to grow the TumorGraft platform, and the balance of the net proceeds for working capital and general corporate purposes. On July 19, 2016, the Company and certain members of its senior management team agreed to exchange existing options to purchase shares of the Company's common stock for new options. The new options have a lower exercise price for fewer shares and have the same vesting schedules and the same termination expiration dates as the existing options. The members of the senior management team whose options were exchanged include Joel Ackerman, the Company's Chief Executive Officer and a member of its Board of Directors, Ronnie Morris, the Company's President and a member of its Board of Directors and David Miller, the Company's Vice President, Finance. As a result of the option exchange, an aggregate of 1,793,781 existing options with exercise prices ranging from $4.55 to $6.96 per share were exchanged for an aggregate of 1,568,191 new options with exercise prices of $2.10 per share. We are currently assessing the accounting impact of this exchange and believe it will not have a material impact on our consolidated financial statements.

Subsequent Events

On June 15, 2016, the Company closed a public offering of 2,000,000 registered shares of its common stock, par value $0.001 per share, at an offering price of $2.25 per share. In addition, the underwriter exercised a partial exercise of the over-allotment option granted to the underwriter to purchase an additional 258,749 shares of its common stock at the public offering price. All of the shares have been offered by the Company.

The net proceeds from the offering, including the partial exercise of the over-allotment option, is approximately $4.3 million million, after deducting the underwriting discount and estimated offering-related expenses of $750,000. The Company intends to use the net proceeds of this offering for research and development to grow the TumorGraft platform, and the balance of the net proceeds for working capital and general corporate purposes.

On July 19, 2016, the Company and certain members of its senior management team agreed to exchange existing options to purchase shares of the Company's common stock for new options. The new options have a lower exercise price for fewer shares and have the same vesting schedules and the same termination expiration dates as the existing options. The members of the senior management team whose options were exchanged include Joel Ackerman, the Company's Chief Executive Officer and a member of its Board of Directors, Ronnie Morris, the Company's President and a member of its Board of Directors and David Miller, the Company's Vice President, Finance. As a result of the option exchange, an aggregate of 1,793,781 existing options with exercise prices ranging from $4.55 to $6.96 per share were exchanged for an aggregate of 1,568,191 new options with exercise prices of $2.10 per share. We are currently assessing the accounting impact of this exchange and believe it will not have a material impact on our consolidated financial statements.