NATURE OF OPERATIONS AND BASIS OF PRESENTATION	3 Months Ended
Mar. 31, 2016
Organization and Nature Of Operations [Abstract]
NATURE OF OPERATIONS AND BASIS OF PRESENTATION	1. NATURE OF OPERATIONS AND BASIS OF PRESENTATION We are a biopharmaceutical company engaged in the research and development of innovative therapeutics to treat cancers and rare diseases. Our mission is to discover, develop and commercialize novel small molecule drugs in areas of high unmet need that will dramatically extend and improve the lives of our patients. These drugs target biological pathways implicated in a wide range of cancers and certain non-oncology indications. Our discovery and development efforts are guided, when possible, by an understanding of the role of biomarkers, which are indicators of a particular biological condition or process and may predict the clinical benefit of our compounds in defined patient populations. Our proprietary clinical-stage pipeline consists of four drug candidates, all of which are in targeted patient populations, making ArQule a leader among companies our size in precision medicine. Our lead product candidate is tivantinib (ARQ 197), an orally administered, small molecule inhibitor of the c-Met receptor tyrosine kinase (“MET”) and its biological pathway. MET is a promising target for cancer therapy, based on its multiple roles in cancerous cell proliferation, tumor spread, new blood vessel formation and resistance to certain drug therapies. We and our partners, Daiichi Sankyo Co., Ltd. (“Daiichi Sankyo”) and Kyowa Hakko Kirin Co., Ltd. (“Kyowa Hakko Kirin”), are implementing a worldwide clinical development program with tivantinib. Our strategy is to focus on the most promising indications within our clinical programs based upon continually generated and updated clinical and pre-clinical data. Our lead indication is liver cancer (“hepatocellular carcinoma” or “HCC”), and we are currently conducting two Phase 3 trials with our partners. We have also completed earlier-stage single agent and combination therapy trials and pre-clinical experiments with tivantinib and other anti-cancer agents that may provide data to support trials in additional indications. On March 22, 2016, we and Daiichi Sankyo announced that the independent data monitoring committee (“DMC”) of the METIV-HCC study conducted the planned interim assessment, and it was determined the trial will continue to its final analysis. Accordingly, we reviewed the estimated development period and extended it to December 2016 for both the METIV-HCC trial and the JET-HCC trial. We have licensed commercial rights to tivantinib for human cancer indications to Daiichi Sankyo in the U.S., Europe, South America and the rest of the world, excluding Japan and certain other Asian countries, where we have licensed commercial rights to Kyowa Hakko Kirin. Our agreements with these partners provide for possible future milestone payments, royalties on product sales, and development funding, in addition to significant payments that we have already received. To date we have received $100 million in upfront and milestone payments from Daiichi Sankyo, $15 million of which was related to the first patient enrolled in the METIV-HCC trial. That milestone was netted against our cumulative share of Phase 3 collaboration costs in 2013, and consequently we did not receive any cash proceeds from this milestone. To date, we have received $48 million in upfront and milestone payments from Kyowa Hakko Kirin. Our proprietary pipeline of product candidates is directed toward molecular targets and biological processes with demonstrated roles in the development of both human cancers and rare, non-oncology diseases. These product candidates include: ARQ 092, designed to inhibit the AKT serine/threonine kinase; ARQ 087, a multi-kinase inhibitor designed to preferentially inhibit the fibroblast growth factor receptor (“FGFR”) family; and ARQ 761, a Beta lapachone analog being evaluated in investigator-sponsored testing as a promoter of NQO1-mediated programmed cancer cell necrosis. We expect to add to our proprietary pipeline with the initiation of a Phase 1 clinical trial in oncology with our next generation AKT inhibitor, ARQ 751, in the first half of 2016. Specific tumor types and biomarkers have been identified to guide our clinical testing, based on analyses of Phase 1a anti-cancer activity in humans, preclinical findings and scientific literature. Our uses of cash for operating activities have primarily consisted of salaries and wages for our employees, facility and facility-related costs for our offices and laboratories, fees paid in connection with preclinical and clinical studies, laboratory supplies and materials, and professional fees. The sources of our cash flow from operating activities have consisted primarily of payments received from our collaborators for services performed or upfront payments for future services. For the quarters ended March 31, 2016 and 2015, our net use of cash was primarily driven by payments for operating expenses which resulted in net cash outflows of $6.4 million and $7.6 million, respectively. Our cash requirements may vary materially from those now planned depending upon the results of our drug discovery and development strategies, our ability to enter into additional corporate collaborations and the terms of such collaborations, results of research and development, unanticipated required capital expenditures, competitive and technological advances, acquisitions and other factors. We cannot guarantee that we will be able to develop any of our drug candidates into a commercial product. It is likely we will need to raise additional capital or incur indebtedness to continue to fund our operations in the future. Our ability to raise additional funds will depend on financial, economic and market conditions, and due to global capital and credit market conditions or for other reasons, we may be unable to raise capital when needed, or on terms favorable to us. If necessary funds are not available, we may have to delay, reduce the scope of, or eliminate some of our development programs, potentially delaying the time to market for any of our product candidates. We have prepared the accompanying condensed financial statements pursuant to the rules and regulations of the U.S. Securities and Exchange Commission (“SEC”). Certain information and footnote disclosures normally included in financial statements prepared in accordance with generally accepted accounting principles have been condensed or omitted pursuant to these rules and regulations. These condensed financial statements should be read in conjunction with our audited financial statements and footnotes related thereto for the year ended December 31, 2015 included in our annual report on Form 10-K filed with the SEC on February 29, 2016. In the opinion of the Company, the accompanying unaudited condensed financial statements contain all adjustments, consisting only of normal recurring adjustments, necessary for a fair statement of its financial position as of March 31, 2016, and its results of operations and cash flows for the three months ended March 31, 2016 and March 31, 2015. The results of operations for such interim periods are not necessarily indicative of the results to be achieved for the full year. The condensed balance sheet at December 31, 2015, was derived from audited annual financial statements, but does not contain all of the footnote disclosures from the annual financial statements.

1. NATURE OF OPERATIONS AND BASIS OF PRESENTATION

We are a biopharmaceutical company engaged in the research and development of innovative therapeutics to treat cancers and rare diseases. Our mission is to discover, develop and commercialize novel small molecule drugs in areas of high unmet need that will dramatically extend and improve the lives of our patients. These drugs target biological pathways implicated in a wide range of cancers and certain non-oncology indications. Our discovery and development efforts are guided, when possible, by an understanding of the role of biomarkers, which are indicators of a particular biological condition or process and may predict the clinical benefit of our compounds in defined patient populations. Our proprietary clinical-stage pipeline consists of four drug candidates, all of which are in targeted patient populations, making ArQule a leader among companies our size in precision medicine.

Our lead product candidate is tivantinib (ARQ 197), an orally administered, small molecule inhibitor of the c-Met receptor tyrosine kinase (“MET”) and its biological pathway. MET is a promising target for cancer therapy, based on its multiple roles in cancerous cell proliferation, tumor spread, new blood vessel formation and resistance to certain drug therapies. We and our partners, Daiichi Sankyo Co., Ltd. (“Daiichi Sankyo”) and Kyowa Hakko Kirin Co., Ltd. (“Kyowa Hakko Kirin”), are implementing a worldwide clinical development program with tivantinib. Our strategy is to focus on the most promising indications within our clinical programs based upon continually generated and updated clinical and pre-clinical data. Our lead indication is liver cancer (“hepatocellular carcinoma” or “HCC”), and we are currently conducting two Phase 3 trials with our partners. We have also completed earlier-stage single agent and combination therapy trials and pre-clinical experiments with tivantinib and other anti-cancer agents that may provide data to support trials in additional indications.

On March 22, 2016, we and Daiichi Sankyo announced that the independent data monitoring committee (“DMC”) of the METIV-HCC study conducted the planned interim assessment, and it was determined the trial will continue to its final analysis. Accordingly, we reviewed the estimated development period and extended it to December 2016 for both the METIV-HCC trial and the JET-HCC trial.

We have licensed commercial rights to tivantinib for human cancer indications to Daiichi Sankyo in the U.S., Europe, South America and the rest of the world, excluding Japan and certain other Asian countries, where we have licensed commercial rights to Kyowa Hakko Kirin. Our agreements with these partners provide for possible future milestone payments, royalties on product sales, and development funding, in addition to significant payments that we have already received. To date we have received $100 million in upfront and milestone payments from Daiichi Sankyo, $15 million of which was related to the first patient enrolled in the METIV-HCC trial. That milestone was netted against our cumulative share of Phase 3 collaboration costs in 2013, and consequently we did not receive any cash proceeds from this milestone. To date, we have received $48 million in upfront and milestone payments from Kyowa Hakko Kirin.

Our proprietary pipeline of product candidates is directed toward molecular targets and biological processes with demonstrated roles in the development of both human cancers and rare, non-oncology diseases. These product candidates include: ARQ 092, designed to inhibit the AKT serine/threonine kinase; ARQ 087, a multi-kinase inhibitor designed to preferentially inhibit the fibroblast growth factor receptor (“FGFR”) family; and ARQ 761, a Beta lapachone analog being evaluated in investigator-sponsored testing as a promoter of NQO1-mediated programmed cancer cell necrosis. We expect to add to our proprietary pipeline with the initiation of a Phase 1 clinical trial in oncology with our next generation AKT inhibitor, ARQ 751, in the first half of 2016. Specific tumor types and biomarkers have been identified to guide our clinical testing, based on analyses of Phase 1a anti-cancer activity in humans, preclinical findings and scientific literature.

Our uses of cash for operating activities have primarily consisted of salaries and wages for our employees, facility and facility-related costs for our offices and laboratories, fees paid in connection with preclinical and clinical studies, laboratory supplies and materials, and professional fees. The sources of our cash flow from operating activities have consisted primarily of payments received from our collaborators for services performed or upfront payments for future services. For the quarters ended March 31, 2016 and 2015, our net use of cash was primarily driven by payments for operating expenses which resulted in net cash outflows of $6.4 million and $7.6 million, respectively.

Our cash requirements may vary materially from those now planned depending upon the results of our drug discovery and development strategies, our ability to enter into additional corporate collaborations and the terms of such collaborations, results of research and development, unanticipated required capital expenditures, competitive and technological advances, acquisitions and other factors. We cannot guarantee that we will be able to develop any of our drug candidates into a commercial product. It is likely we will need to raise additional capital or incur indebtedness to continue to fund our operations in the future. Our ability to raise additional funds will depend on financial, economic and market conditions, and due to global capital and credit market conditions or for other reasons, we may be unable to raise capital when needed, or on terms favorable to us. If necessary funds are not available, we may have to delay, reduce the scope of, or eliminate some of our development programs, potentially delaying the time to market for any of our product candidates.

We have prepared the accompanying condensed financial statements pursuant to the rules and regulations of the U.S. Securities and Exchange Commission (“SEC”). Certain information and footnote disclosures normally included in financial statements prepared in accordance with generally accepted accounting principles have been condensed or omitted pursuant to these rules and regulations. These condensed financial statements should be read in conjunction with our audited financial statements and footnotes related thereto for the year ended December 31, 2015 included in our annual report on Form 10-K filed with the SEC on February 29, 2016.

In the opinion of the Company, the accompanying unaudited condensed financial statements contain all adjustments, consisting only of normal recurring adjustments, necessary for a fair statement of its financial position as of March 31, 2016, and its results of operations and cash flows for the three months ended March 31, 2016 and March 31, 2015. The results of operations for such interim periods are not necessarily indicative of the results to be achieved for the full year. The condensed balance sheet at December 31, 2015, was derived from audited annual financial statements, but does not contain all of the footnote disclosures from the annual financial statements.