Business	6 Months Ended
Jun. 30, 2020
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Business	1. Business We are a commercial-stage biotechnology company focused on improving the lives of patients by developing best-in-class treatments to address some of the most important unmet patient needs. We are developing novel, patient-focused solutions that apply our innovative science and technologies to already-approved pharmacological agents for patients suffering from pain or cancer. In August 2016, our first commercial product, SUSTOL (granisetron) extended-release injection (“SUSTOL”), was approved by the U.S. Food and Drug Administration (“FDA”). SUSTOL is indicated in combination with other antiemetics in adults for the prevention of acute and delayed nausea and vomiting associated with initial and repeat courses of moderately emetogenic chemotherapy (MEC) or anthracycline and cyclophosphamide (AC) combination chemotherapy regimens. SUSTOL is an extended-release, injectable 5-hydroxytryptamine type 3 receptor antagonist that utilizes our proprietary Biochronomer drug delivery technology to maintain therapeutic levels of granisetron for ≥5 days. We commenced commercial sales of SUSTOL in the U.S. in October 2016. In November 2017, our second commercial product, CINVANTI (aprepitant) injectable emulsion (“CINVANTI”) was approved by the FDA. In October 2019, the FDA approved our supplemental New Drug Application (“sNDA”) for CINVANTI to expand the indication and recommended dosage to include the 130 mg single-dose regimen for patients receiving moderately emetogenic cancer chemotherapy (“MEC”). CINVANTI, in combination with other antiemetic agents, is indicated in adults for the prevention of acute and delayed nausea and vomiting associated with initial and repeat courses of highly emetogenic cancer chemotherapy (HEC) including high-dose cisplatin as a single-dose regimen, delayed nausea and vomiting associated with initial and repeat courses of moderately emetogenic cancer chemotherapy (MEC) as a single-dose regimen, and nausea and vomiting associated with initial and repeat courses of MEC as a 3-day regimen. CINVANTI is an intravenous (“IV”) formulation of aprepitant, a substance P/neurokinin-1 (“NK₁”) receptor antagonist. CINVANTI is the first and only IV formulation of an NK₁ receptor antagonist indicated for the prevention of acute and delayed nausea and vomiting associated with HEC and nausea and vomiting associated with MEC that is free of synthetic surfactants, including polysorbate 80. We commenced commercial sales of CINVANTI in the U.S. in January 2018. In February 2019, the FDA approved our sNDA for CINVANTI, for IV use, which expanded the administration of CINVANTI beyond the initially approved administration method (a 30-minute IV infusion) to include a 2-minute IV injection. CINVANTI is under investigation for the treatment of Coronavirus Disease 2019 (“COVID-19”) as a daily 2-minute IV injection when added to the current standard of care. HTX-011 (ZYNRELEF in the European Union), an investigational non-opioid, is a dual-acting, fixed-dose combination of the local anesthetic bupivacaine with a low dose of the nonsteroidal anti-inflammatory drug meloxicam. It is the first and only extended-release local anesthetic to demonstrate in Phase 3 studies significantly reduced pain and opioid use through 72 hours compared to bupivacaine solution, the current standard-of-care local anesthetic for postoperative pain control. HTX-011 was granted Fast Track designation from the FDA in the fourth quarter of 2017 and Breakthrough Therapy designation in the second quarter of 2018. Heron submitted a New Drug Application (“NDA”) to the FDA for HTX-011 in October 2018 and received Priority Review designation in December 2018. A Complete Response Letter (“CRL”) was received from the FDA regarding the NDA for HTX-011 on June 26, 2020. The CRL stated that the FDA is unable to approve the NDA in its present form based on the need for additional non-clinical information. Based on the complete review of the NDA, the FDA did not identify any clinical safety or efficacy issues or chemistry, manufacturing and controls issues. There are four non-clinical issues in the CRL, none of which relate to any observed toxicity. Three relate to confirming exposure of excipients in preclinical reproductive toxicology studies, and the fourth relates to changing the manufacturing release specification of the allowable level of an impurity based on animal toxicology coverage. The European Medicines Agency’s Committee for Medicinal Products for Human Use (“CHMP”) adopted a positive opinion for ZYNRELEF in July 2020. The CHMP’s positive opinion will now be reviewed by the European Commission (“EC”), with a final decision on the Marketing Authorisation Application expected in the coming months. An EC marketing authorisation through the Centralised Procedure is valid in all 27 European Union member countries as well as the European Economic Area countries. The CHMP recommended that ZYNRELEF be indicated for treatment of somatic postoperative pain from small- to medium-sized surgical wounds in adults. Heron’s New Drug Submission for HTX-011 for the management of postoperative pain was granted Priority Review status by Health Canada in October 2019 and accepted by Health Canada in November 2019. Heron is working to respond to a list of questions received from Health Canada in July 2020. HTX-034, our next-generation product candidate for postoperative pain management, is an investigational non-opioid, fixed-dose combination, extended‑release solution of the local anesthetic bupivacaine, the nonsteroidal anti-inflammatory drug meloxicam and an additional agent that further potentiates the activity of bupivacaine. HTX-034 is formulated in the same proprietary polymer as HTX-011 (ZYNRELEF in the European Union). By combining two different mechanisms that each enhance the activity of the local anesthetic bupivacaine, HTX-034 is designed to provide superior and prolonged analgesia. Local administration of HTX-034 in a validated preclinical postoperative pain model resulted in sustained analgesia for 7 days. In May 2020, we initiated a Phase 1b/2 clinical study in patients undergoing bunionectomy of HTX-034. The study initiation follows clearance from the FDA of our Investigational New Drug application for HTX-034 for the treatment of postoperative pain. As of June 30, 2020 we had $300.8 million in cash, cash equivalents and short-term investments. We have incurred significant operating losses and negative cash flows from operations. Management believes that the Company’s existing cash, cash equivalents and short-term investments will be sufficient to meet the Company’s anticipated cash requirements for at least one year from the date this Quarterly Report on Form 10-Q is filed with the U.S. Securities and Exchange Commission (“SEC”).

Business

6 Months Ended

Jun. 30, 2020

Organization Consolidation And Presentation Of Financial Statements [Abstract]

1. Business

We are a commercial-stage biotechnology company focused on improving the lives of patients by developing best-in-class treatments to address some of the most important unmet patient needs. We are developing novel, patient-focused solutions that apply our innovative science and technologies to already-approved pharmacological agents for patients suffering from pain or cancer.

In August 2016, our first commercial product, SUSTOL (granisetron) extended-release injection (“SUSTOL”), was approved by the U.S. Food and Drug Administration (“FDA”). SUSTOL is indicated in combination with other antiemetics in adults for the prevention of acute and delayed nausea and vomiting associated with initial and repeat courses of moderately emetogenic chemotherapy (MEC) or anthracycline and cyclophosphamide (AC) combination chemotherapy regimens. SUSTOL is an extended-release, injectable 5-hydroxytryptamine type 3 receptor antagonist that utilizes our proprietary Biochronomer drug delivery technology to maintain therapeutic levels of granisetron for ≥5 days. We commenced commercial sales of SUSTOL in the U.S. in October 2016.

In November 2017, our second commercial product, CINVANTI (aprepitant) injectable emulsion (“CINVANTI”) was approved by the FDA. In October 2019, the FDA approved our supplemental New Drug Application (“sNDA”) for CINVANTI to expand the indication and recommended dosage to include the 130 mg single-dose regimen for patients receiving moderately emetogenic cancer chemotherapy (“MEC”). CINVANTI, in combination with other antiemetic agents, is indicated in adults for the prevention of acute and delayed nausea and vomiting associated with initial and repeat courses of highly emetogenic cancer chemotherapy (HEC) including high-dose cisplatin as a single-dose regimen, delayed nausea and vomiting associated with initial and repeat courses of moderately emetogenic cancer chemotherapy (MEC) as a single-dose regimen, and nausea and vomiting associated with initial and repeat courses of MEC as a 3-day regimen. CINVANTI is an intravenous (“IV”) formulation of aprepitant, a substance P/neurokinin-1 (“NK₁”) receptor antagonist. CINVANTI is the first and only IV formulation of an NK₁ receptor antagonist indicated for the prevention of acute and delayed nausea and vomiting associated with HEC and nausea and vomiting associated with MEC that is free of synthetic surfactants, including polysorbate 80. We commenced commercial sales of CINVANTI in the U.S. in January 2018. In February 2019, the FDA approved our sNDA for CINVANTI, for IV use, which expanded the administration of CINVANTI beyond the initially approved administration method (a 30-minute IV infusion) to include a 2-minute IV injection. CINVANTI is under investigation for the treatment of Coronavirus Disease 2019 (“COVID-19”) as a daily 2-minute IV injection when added to the current standard of care.

HTX-011 (ZYNRELEF in the European Union), an investigational non-opioid, is a dual-acting, fixed-dose combination of the local anesthetic bupivacaine with a low dose of the nonsteroidal anti-inflammatory drug meloxicam. It is the first and only extended-release local anesthetic to demonstrate in Phase 3 studies significantly reduced pain and opioid use through 72 hours compared to bupivacaine solution, the current standard-of-care local anesthetic for postoperative pain control. HTX-011 was granted Fast Track designation from the FDA in the fourth quarter of 2017 and Breakthrough Therapy designation in the second quarter of 2018. Heron submitted a New Drug Application (“NDA”) to the FDA for HTX-011 in October 2018 and received Priority Review designation in December 2018. A Complete Response Letter (“CRL”) was received from the FDA regarding the NDA for HTX-011 on June 26, 2020. The CRL stated that the FDA is unable to approve the NDA in its present form based on the need for additional non-clinical information. Based on the complete review of the NDA, the FDA did not identify any clinical safety or efficacy issues or chemistry, manufacturing and controls issues. There are four non-clinical issues in the CRL, none of which relate to any observed toxicity. Three relate to confirming exposure of excipients in preclinical reproductive toxicology studies, and the fourth relates to changing the manufacturing release specification of the allowable level of an impurity based on animal toxicology coverage. The European Medicines Agency’s Committee for Medicinal Products for Human Use (“CHMP”) adopted a positive opinion for ZYNRELEF in July 2020. The CHMP’s positive opinion will now be reviewed by the European Commission (“EC”), with a final decision on the Marketing Authorisation Application expected in the coming months. An EC marketing authorisation through the Centralised Procedure is valid in all 27 European Union member countries as well as the European Economic Area countries. The CHMP recommended that ZYNRELEF be indicated for treatment of somatic postoperative pain from small- to medium-sized surgical wounds in adults. Heron’s New Drug Submission for HTX-011 for the management of postoperative pain was granted Priority Review status by Health Canada in October 2019 and accepted by Health Canada in November 2019. Heron is working to respond to a list of questions received from Health Canada in July 2020.

HTX-034, our next-generation product candidate for postoperative pain management, is an investigational non-opioid, fixed-dose combination, extended‑release solution of the local anesthetic bupivacaine, the nonsteroidal anti-inflammatory drug meloxicam and an additional agent that further potentiates the activity of bupivacaine. HTX-034 is formulated in the same proprietary polymer as HTX-011 (ZYNRELEF in the European Union). By combining two different mechanisms that each enhance the activity of the local anesthetic bupivacaine, HTX-034 is designed to provide superior and prolonged analgesia. Local administration of HTX-034 in a validated preclinical postoperative pain model resulted in sustained analgesia for 7 days. In May 2020, we initiated a Phase 1b/2 clinical study in patients undergoing bunionectomy of HTX-034. The study initiation follows clearance from the FDA of our Investigational New Drug application for HTX-034 for the treatment of postoperative pain.

As of June 30, 2020 we had $300.8 million in cash, cash equivalents and short-term investments. We have incurred significant operating losses and negative cash flows from operations. Management believes that the Company’s existing cash, cash equivalents and short-term investments will be sufficient to meet the Company’s anticipated cash requirements for at least one year from the date this Quarterly Report on Form 10-Q is filed with the U.S. Securities and Exchange Commission (“SEC”).