Debt	9 Months Ended
Sep. 30, 2019
Debt Disclosure [Abstract]
Debt	Note 5. Debt Long-term debt with Western Alliance Bank On October 12, 2018, the Company entered into a Loan and Security Agreement with Western Alliance Bank (the “Bank”) whereby the Company received gross proceeds of $10.0 million under a long-term debt agreement (the “Loan”). The Loan has a maturity date of October 1, 2022 and carries interest at the U.S. prime rate plus 1.25%. The loan has an interest-only period of 19 months, which could be extended by an additional 6 months if certain conditions are met, followed by an amortization period of 30 months, or 24 months if the interest-only period is extended. The Company paid a loan origination fee of $128,000 which was recorded as a debt discount and is being accreted over the term of the Loan. In addition, the Company is required to pay a fee of $350,000 upon certain change of control events. Upon maturity or prepayment, the Company will be required to pay a 3% fee, or a 2% fee if the U.S. Food and Drug Administration accepts certain IND applications prior to maturity. Because acceptance of an IND is outside of the Company’s control, management estimated that the Company will be liable for a fee of 3% of the principal balance, or $300,000 upon repayment or maturity, and such fee is accreted to the debt balance using the effective interest method over the term of the Loan. The Loan is collateralized by all of the assets of the Company, excluding intellectual property, which is subject to a negative pledge. The Loan contains customary conditions of borrowing, events of default and covenants, including covenants that restrict the Company’s ability to dispose of assets, merge with or acquire other entities, incur indebtedness and make distributions to holders of the Company’s capital stock. In addition, the Company is required to maintain at least 50% of its deposit and investment accounts, or $20 million, whichever is lower, with Western Alliance Bank. The Loan also includes covenants which include the Company’s (1) nomination of a clinical candidate by December 31, 2018, which the Company is in compliance with, and (2) submission of a clinical candidate for IND application, made to the U.S. Food and Drug Administration by December 31, 2019 and have it approved by January 31, 2020, provided that, if the Company has received net cash proceeds from sale, on or after October 12, 2018, of the Company’s equity securities in an amount of not less than $15,000,000, then the IND submission date shall be extended to May 31, 2020 and the approval date shall be extended to June 30, 2020. As a result of the equity purchase by Ultragenyx of 2.4 million shares of common stock (previously discussed at Note 2), the IND submission date and approval date have been extended to May 31, 2020 and June 30, 2020, respectively. Should an event of default occur, including the occurrence of a material adverse effect, the Company could be liable for immediate repayment of all obligations under the Loan. As of September 30, 2019, the Company is in compliance with all covenants and conditions of the Loan. On October 30, 2019, Arcturus Therapeutics, Inc. (the “Borrower”), a wholly-owned subsidiary of the Company and the Bank entered into a Third Amendment (the “Third Amendment”) to the Loan and Security Agreement dated as of October 12, 2018 (as amended, the “Loan Agreement”). Pursuant to the amendment, the Bank agreed to make a term loan to the Company on October 30, 2019, in the amount of $15 million (the “Term Loan”). After repaying $10 million for the Loan the Company owed to the Bank, the resulting net increase in the indebtedness of the Company was $5 million. The Term Loan bears interest at a floating rate ranging from 1.25% to 2.75% above the prime rate. The amendment further provides that the Term Loan has a maturity date of October 30, 2023. The Company shall make monthly payments of interest only until the interest-only end date of April 1, 2021, which is subject to extension to October 1, 2021 upon the occurrence of an equity or expansion event and the absence of an event of default, and thereafter shall make monthly payments of principal and interest during a 30-month amortization period. The Term Loan may be prepaid in full at any time, provided that a prepayment fee is required to be paid by the Company upon prepayment. The prepayment fee ranges from 0.50% to 2.00% of the prepaid principal amount depending upon the date on which the prepayment is made. In connection with the Third Amendment, the Company guaranteed the Borrower’s obligations under the Loan Agreement and pledged substantially all of its assets as security under the Loan Agreement. The amendment also modified the Company’s covenants to extend the dates by which a selected IND must be submitted and by which the U.S. Food and Drug Administration or equivalent authority must accept the IND, and also required the Company to maintain the lesser of (i) all of its total consolidated and unrestricted cash in total deposits with the Bank or (ii) $15 million in total deposits with the Bank.

Debt

9 Months Ended

Sep. 30, 2019

Note 5. Debt

Long-term debt with Western Alliance Bank

On October 12, 2018, the Company entered into a Loan and Security Agreement with Western Alliance Bank (the “Bank”) whereby the Company received gross proceeds of $10.0 million under a long-term debt agreement (the “Loan”). The Loan has a maturity date of October 1, 2022 and carries interest at the U.S. prime rate plus 1.25%. The loan has an interest-only period of 19 months, which could be extended by an additional 6 months if certain conditions are met, followed by an amortization period of 30 months, or 24 months if the interest-only period is extended.

The Company paid a loan origination fee of $128,000 which was recorded as a debt discount and is being accreted over the term of the Loan. In addition, the Company is required to pay a fee of $350,000 upon certain change of control events.

Upon maturity or prepayment, the Company will be required to pay a 3% fee, or a 2% fee if the U.S. Food and Drug Administration accepts certain IND applications prior to maturity. Because acceptance of an IND is outside of the Company’s control, management estimated that the Company will be liable for a fee of 3% of the principal balance, or $300,000 upon repayment or maturity, and such fee is accreted to the debt balance using the effective interest method over the term of the Loan.

The Loan is collateralized by all of the assets of the Company, excluding intellectual property, which is subject to a negative pledge. The Loan contains customary conditions of borrowing, events of default and covenants, including covenants that restrict the Company’s ability to dispose of assets, merge with or acquire other entities, incur indebtedness and make distributions to holders of the Company’s capital stock. In addition, the Company is required to maintain at least 50% of its deposit and investment accounts, or $20 million, whichever is lower, with Western Alliance Bank.

The Loan also includes covenants which include the Company’s (1) nomination of a clinical candidate by December 31, 2018, which the Company is in compliance with, and (2) submission of a clinical candidate for IND application, made to the U.S. Food and Drug Administration by December 31, 2019 and have it approved by January 31, 2020, provided that, if the Company has received net cash proceeds from sale, on or after October 12, 2018, of the Company’s equity securities in an amount of not less than $15,000,000, then the IND submission date shall be extended to May 31, 2020 and the approval date shall be extended to June 30, 2020. As a result of the equity purchase by Ultragenyx of 2.4 million shares of common stock (previously discussed at Note 2), the IND submission date and approval date have been extended to May 31, 2020 and June 30, 2020, respectively.

Should an event of default occur, including the occurrence of a material adverse effect, the Company could be liable for immediate repayment of all obligations under the Loan. As of September 30, 2019, the Company is in compliance with all covenants and conditions of the Loan.

On October 30, 2019, Arcturus Therapeutics, Inc. (the “Borrower”), a wholly-owned subsidiary of the Company and the Bank entered into a Third Amendment (the “Third Amendment”) to the Loan and Security Agreement dated as of October 12, 2018 (as amended, the “Loan Agreement”).

Pursuant to the amendment, the Bank agreed to make a term loan to the Company on October 30, 2019, in the amount of $15 million (the “Term Loan”). After repaying $10 million for the Loan the Company owed to the Bank, the resulting net increase in the indebtedness of the Company was $5 million. The Term Loan bears interest at a floating rate ranging from 1.25% to 2.75% above the prime rate. The amendment further provides that the Term Loan has a maturity date of October 30, 2023. The Company shall make monthly payments of interest only until the interest-only end date of April 1, 2021, which is subject to extension to October 1, 2021 upon the occurrence of an equity or expansion event and the absence of an event of default, and thereafter shall make monthly payments of principal and interest during a 30-month amortization period.

The Term Loan may be prepaid in full at any time, provided that a prepayment fee is required to be paid by the Company upon prepayment. The prepayment fee ranges from 0.50% to 2.00% of the prepaid principal amount depending upon the date on which the prepayment is made. In connection with the Third Amendment, the Company guaranteed the Borrower’s obligations under the Loan Agreement and pledged substantially all of its assets as security under the Loan Agreement.

The amendment also modified the Company’s covenants to extend the dates by which a selected IND must be submitted and by which the U.S. Food and Drug Administration or equivalent authority must accept the IND, and also required the Company to maintain the lesser of (i) all of its total consolidated and unrestricted cash in total deposits with the Bank or (ii) $15 million in total deposits with the Bank.