5. Stockholders' Equity	9 Months Ended
Jan. 31, 2021
Equity [Abstract]
Stockholders' Equity	Note 5 – Stockholders’ Equity Series E Preferred Stock Each share of issued and outstanding 10.50% Series E Convertible Preferred Stock $0.001 par value per share (“Series E Preferred Stock”) is convertible at any time, at the option of the holder, into a number of shares of our common stock determined by dividing the liquidation preference of $25.00 per share Series E Preferred Stock, plus any accrued and unpaid dividends (whether or not earned or declared), by the then-current conversion price per share, currently $21.00 per share, rounded down to the nearest whole number. As of January 31, 2021, if all of our issued and outstanding shares of Series E Preferred Stock were converted at the conversion price of $21.00 per share, the holders of our Series E Preferred Stock would receive an aggregate of 1,978,783 shares of our common stock. However, because the conversion price of our Series E Preferred Stock is subject to adjustment from time to time in accordance with the applicable provisions of our certificate of incorporation, we have reserved the maximum number of shares of our common stock that could be issued upon the conversion of our Series E Preferred Stock upon a change of control event, assuming our shares of common stock are acquired for consideration of $5.985 per share or less. In this scenario, each outstanding share of our Series E Preferred Stock would be converted into 4.14 shares of our common stock, or 6,826,435 shares in the aggregate. The Series E Preferred Stock has no stated maturity date or mandatory redemption and is senior to all of our other securities. We may redeem the Series E Preferred Stock for cash, in whole or in part, by paying the redemption price of $25.00 per share, plus any accrued and unpaid dividends to the redemption date. Holders of the Series E Preferred Stock have no voting rights, except as defined in the Certificate of Designations of Rights and Preferences filed with the Secretary of State of the State of Delaware on February 12, 2014. Holders of our Series E Preferred Stock are entitled to receive cumulative dividends at the rate of 10.50% per annum based on the liquidation preference of $25.00 per share, or $2.625 per annum per share, and are payable quarterly in cash, on or about the first day of each January, April, July and October. For each of the three and nine months ended January 31, 2021 and 2020, we paid aggregate cash dividends of $1.1 million and $3.2 million, respectively, for issued and outstanding shares of our Series E Preferred Stock. Sale of Common Stock During December 2020, we completed an underwritten public offering pursuant to which we sold 3,833,335 shares of our common stock at the public offering price of $9.00 per share, including 500,000 shares sold pursuant to the underwriters’ full exercise of their option to purchase additional shares. The aggregate gross proceeds we received from the public offering were $34.5 million, before deducting underwriting discounts and commissions and other offering related expenses of $2.4 million.

5. Stockholders' Equity

9 Months Ended

Jan. 31, 2021

Note 5 – Stockholders’ Equity

Series E Preferred Stock

Each share of issued and outstanding 10.50% Series E Convertible Preferred Stock $0.001 par value per share (“Series E Preferred Stock”) is convertible at any time, at the option of the holder, into a number of shares of our common stock determined by dividing the liquidation preference of $25.00 per share Series E Preferred Stock, plus any accrued and unpaid dividends (whether or not earned or declared), by the then-current conversion price per share, currently $21.00 per share, rounded down to the nearest whole number. As of January 31, 2021, if all of our issued and outstanding shares of Series E Preferred Stock were converted at the conversion price of $21.00 per share, the holders of our Series E Preferred Stock would receive an aggregate of 1,978,783 shares of our common stock. However, because the conversion price of our Series E Preferred Stock is subject to adjustment from time to time in accordance with the applicable provisions of our certificate of incorporation, we have reserved the maximum number of shares of our common stock that could be issued upon the conversion of our Series E Preferred Stock upon a change of control event, assuming our shares of common stock are acquired for consideration of $5.985 per share or less. In this scenario, each outstanding share of our Series E Preferred Stock would be converted into 4.14 shares of our common stock, or 6,826,435 shares in the aggregate.

The Series E Preferred Stock has no stated maturity date or mandatory redemption and is senior to all of our other securities. We may redeem the Series E Preferred Stock for cash, in whole or in part, by paying the redemption price of $25.00 per share, plus any accrued and unpaid dividends to the redemption date. Holders of the Series E Preferred Stock have no voting rights, except as defined in the Certificate of Designations of Rights and Preferences filed with the Secretary of State of the State of Delaware on February 12, 2014.

Holders of our Series E Preferred Stock are entitled to receive cumulative dividends at the rate of 10.50% per annum based on the liquidation preference of $25.00 per share, or $2.625 per annum per share, and are payable quarterly in cash, on or about the first day of each January, April, July and October. For each of the three and nine months ended January 31, 2021 and 2020, we paid aggregate cash dividends of $1.1 million and $3.2 million, respectively, for issued and outstanding shares of our Series E Preferred Stock.

Sale of Common Stock

During December 2020, we completed an underwritten public offering pursuant to which we sold 3,833,335 shares of our common stock at the public offering price of $9.00 per share, including 500,000 shares sold pursuant to the underwriters’ full exercise of their option to purchase additional shares. The aggregate gross proceeds we received from the public offering were $34.5 million, before deducting underwriting discounts and commissions and other offering related expenses of $2.4 million.