A change in the outcome of any of these variables with respect to the development of any of our product candidates would significantly change the costs and timing associated with the development of that product candidate.
We will not generate revenue from product sales unless and until we or a collaborator successfully complete clinical development and obtain regulatory approval for our current and future product candidates. If we obtain regulatory approval for any of our product candidates that we intend to commercialize on our own, we will incur significant expenses related to commercialization, including developing our internal commercialization capability to support product sales, marketing and distribution.
As a result, we will need substantial additional funding to support our continuing operations and to pursue our growth strategy. Until such time, if ever, when we can generate substantial product revenue, we expect to finance our cash needs through a combination of equity offerings, debt financings and potential collaboration, license and development agreements. Debt financing and preferred equity financing, if available, may involve agreements that include covenants limiting or restricting our ability to take specific actions, such as incurring additional debt, making capital expenditures or declaring dividends.
If we raise additional funds through collaborations, strategic alliances or marketing, distribution or licensing arrangements with third parties, we may be required to relinquish valuable rights to our technologies, future revenue streams, research programs or product candidates or to grant licenses on terms that may not be favorable to us. If we are unable to raise additional funds through equity or debt financings when needed, we may be required to delay, limit, reduce or terminate our drug development or future commercialization efforts or grant rights to a third party to develop and market product candidates that we would otherwise prefer to develop and market ourselves. Our failure to raise capital as and when needed would compromise our ability to pursue our business strategy.
Because of the numerous risks and uncertainties associated with product development, we are unable to predict the timing or amount of increased expenses or when or if we will be able to achieve or maintain profitability. Even if we are able to generate product sales, we may not become profitable. If we fail to become profitable or are unable to sustain profitability on a continuing basis, we may be unable to continue our operations at planned levels and be forced to reduce or terminate our operations.
Aspire Common Stock Purchase Agreement
In October 2019, we entered into a common stock purchase agreement, or CSPA, with Aspire Capital Fund, LLC, or Aspire, which provides that, upon the terms and subject to the conditions and limitations set forth therein, Aspire is committed to purchase up to an aggregate of $20.0 million of shares of our common stock over the 30-month term of the CSPA. Under the CSPA, on any trading day selected by us on which the closing price of our common stock is equal to or greater than $0.25 per share, we have the right, in our sole discretion, to present Aspire with a purchase notice directing Aspire to purchase up to 50,000 shares of our common stock per business day, at a purchase price equal to the lesser of the lowest sale price of common stock on the purchase date, or the arithmetic average of the three lowest closing sale prices during the 10 consecutive business days ending on the trading day immediately preceding the purchase date. We and Aspire also may mutually agree to increase the number of shares that may be sold to as much as 2,000,000 shares per business day.
We control the timing and amount of any sales to Aspire, and we are not limited with respect to use of proceeds or by any financial or business covenants, restrictions on future financings, rights of first refusal, participation rights, penalties or liquidated damages in the CSPA. The CSPA further provides that the number of shares that may be sold pursuant to the CSPA will be limited to 2,626,165 shares, which represented 19.99% of our outstanding shares of common stock as of October 21, 2019, unless stockholder approval is obtained to issue more than 19.99%. To date, we have not sold any shares to Aspire pursuant to the CSPA.
Innoviva, Inc. Securities Purchase Agreement
On May 3, 2021, we entered into a securities purchase agreement, or the Securities Purchase Agreement, with a subsidiary of Innoviva, Inc., or Innoviva, pursuant to which we agreed to issue and sell to Innoviva, in a private