Collaboration and Licensing Agreements	3 Months Ended
Mar. 31, 2018
Collaboration and Licensing Agreements [Abstract]
Collaboration and Licensing Agreements	NOTE 8. COLLABORATION AND LICENSING AGREEMENTS Kyowa Hakko Kirin Co., Ltd., or KHK In November 2017, the Company entered into an exclusive license agreement with KHK, or the KHK Agreement, for the development, commercialization and distribution of tenapanor in Japan for cardiorenal indications. The Company assessed these arrangements in accordance with Topic 606 and concluded that the contract counterparty, KHK, is a customer. Under the terms of the KHK Agreement, the Company received $30.0 million in up-front license fees which was recognized as revenue when the agreement was executed. Based on the Company’s assessment, it identified that the license and the manufacturing supply services were its material performance obligations at the inception of the agreement, and as such each of the performance obligations are distinct. Additionally, on January 1, 2018, the Company recorded an increase in current assets of $5.0 million as well as in current liabilities of $1.0 million related to the first milestone under the KHK Agreement which the Company believes is not materially at risk, reflecting revenues and cost of revenue, respectively, that would have been recognized in the fourth quarter 2017 if the Company had adopted Topic 606 prior to January 1, 2018. In addition to the up-front license fee of $30.0 million, the Company may be entitled to receive up to $55.0 million in total development milestones and 8.5 billion yen in commercialization milestones, as well as reimbursement of cost plus a reasonable overhead for the supply of product and high-teen royalties on net sales throughout the term of the agreement. There was no revenue recorded in the period ended March 31, 2018 related to the KHK Agreement. Shanghai Fosun Pharmaceutical Industrial Development Co. Ltd., or Fosun Pharma In December 2017, the Company entered into an exclusive license agreement with Fosun Pharma, or the Fosun Agreement, for the development, commercialization and distribution of tenapanor in China for both hyperphosphatemia and irritable bowel syndrome with constipation, or IBS-C. The Company assessed these arrangements in accordance with Topic 606 and concluded that the contract counterparty, Fosun Pharma, is a customer. Under the terms of the Fosun Agreement, the Company received $12.0 million in up-front license fees which was recognized as revenue when the agreement was executed. Based on the Company’s assessment, it identified that the license and the manufacturing supply services were its material performance obligations at the inception of the agreement, and as such each of the performance obligations are distinct. In addition, the Company may be entitled to additional development and commercialization milestones of up to $113.0 million, as well as reimbursement of cost plus a reasonable overhead for the supply of product and tiered royalties on net sales ranging from the mid-teens to 20%. There was no revenue recorded in the period ended March 31, 2018 related to the Fosun Agreement. Knight Therapeutics, Inc., or Knight In March 2018, the Company entered into an exclusive license agreement with Knight Therapeutics, Inc., or the Knight Agreement, for the development, commercialization and distribution of tenapanor in Canada for hyperphosphatemia and IBS-C. The Company assessed these arrangements in accordance with Topic 606 and concluded that the contract counterparty, Knight, is a customer. Based on the Company’s assessment, it identified that the license and the manufacturing supply services were its material performance obligations at the inception of the agreement, and as such each of the performance obligations are distinct. Under the terms of the agreement, the Company is eligible to receive up to CAD 25 million in total payments including an up-front payment and development and sales milestones, reimbursement of supply costs on a schedule specifying cost per tablet, with a reasonable mark up for overhead, as well as double-digit tiered royalties on net sales. In the period ended March 31, 2018, there was $2.3 million of revenue recorded related to the Knight Agreement and $0.5 million of cost of revenue pursuant to the AstraZeneca Termination Agreement. AstraZeneca In June 2015, the Company entered into a termination agreement with AstraZeneca, or the Termination Agreement, pursuant to which the Company remains liable to pay AstraZeneca license fees for (i) future royalties at a royalty rate of 10% of net sales of tenapanor or other NHE3 products by the Company or its licensees, and (ii) 20% of non-royalty revenue received from a new collaboration partner should the Company elect to license, or otherwise provide rights to develop and commercialize tenapanor or another NHE3 inhibitor, up to a maximum of $75.0 million in aggregate for (i) and (ii). To date in aggregate, the Company has recognized $9.9 million of the $75.0 million, recorded as cost of revenue comprising (i) $6.0 million and $2.4 million related to the KHK Agreement and Fosun Agreement, respectively, recorded in 2017 (ii) $1.0 million related to the KHK Agreement associated with a future milestone which the Company believes is not materially at risk for which the Company recorded an increase in current liabilities in the period ended March 31, 2018 reflecting the future payable to AstraZeneca and (iii) $0.5 million related to the Knight Agreement recorded in the period ended March 31, 2018.

NOTE 8. COLLABORATION AND LICENSING AGREEMENTS

Kyowa Hakko Kirin Co., Ltd., or KHK

In November 2017, the Company entered into an exclusive license agreement with KHK, or the KHK Agreement, for the development, commercialization and distribution of tenapanor in Japan for cardiorenal indications. The Company assessed these arrangements in accordance with Topic 606 and concluded that the contract counterparty, KHK, is a customer. Under the terms of the KHK Agreement, the Company received $30.0 million in up-front license fees which was recognized as revenue when the agreement was executed. Based on the Company’s assessment, it identified that the license and the manufacturing supply services were its material performance obligations at the inception of the agreement, and as such each of the performance obligations are distinct. Additionally, on January 1, 2018, the Company recorded an increase in current assets of $5.0 million as well as in current liabilities of $1.0 million related to the first milestone under the KHK Agreement which the Company believes is not materially at risk, reflecting revenues and cost of revenue, respectively, that would have been recognized in the fourth quarter 2017 if the Company had adopted Topic 606 prior to January 1, 2018.

In addition to the up-front license fee of $30.0 million, the Company may be entitled to receive up to $55.0 million in total development milestones and 8.5 billion yen in commercialization milestones, as well as reimbursement of cost plus a reasonable overhead for the supply of product and high-teen royalties on net sales throughout the term of the agreement.

There was no revenue recorded in the period ended March 31, 2018 related to the KHK Agreement.

Shanghai Fosun Pharmaceutical Industrial Development Co. Ltd., or Fosun Pharma

In December 2017, the Company entered into an exclusive license agreement with Fosun Pharma, or the Fosun Agreement, for the development, commercialization and distribution of tenapanor in China for both hyperphosphatemia and irritable bowel syndrome with constipation, or IBS-C. The Company assessed these arrangements in accordance with Topic 606 and concluded that the contract counterparty, Fosun Pharma, is a customer. Under the terms of the Fosun Agreement, the Company received $12.0 million in up-front license fees which was recognized as revenue when the agreement was executed. Based on the Company’s assessment, it identified that the license and the manufacturing supply services were its material performance obligations at the inception of the agreement, and as such each of the performance obligations are distinct.

In addition, the Company may be entitled to additional development and commercialization milestones of up to $113.0 million, as well as reimbursement of cost plus a reasonable overhead for the supply of product and tiered royalties on net sales ranging from the mid-teens to 20%.

There was no revenue recorded in the period ended March 31, 2018 related to the Fosun Agreement.

Knight Therapeutics, Inc., or Knight

In March 2018, the Company entered into an exclusive license agreement with Knight Therapeutics, Inc., or the Knight Agreement, for the development, commercialization and distribution of tenapanor in Canada for hyperphosphatemia and IBS-C. The Company assessed these arrangements in accordance with Topic 606 and concluded that the contract counterparty, Knight, is a customer. Based on the Company’s assessment, it identified that the license and the manufacturing supply services were its material performance obligations at the inception of the agreement, and as such each of the performance obligations are distinct.

Under the terms of the agreement, the Company is eligible to receive up to CAD 25 million in total payments including an up-front payment and development and sales milestones, reimbursement of supply costs on a schedule specifying cost per tablet, with a reasonable mark up for overhead, as well as double-digit tiered royalties on net sales.

In the period ended March 31, 2018, there was $2.3 million of revenue recorded related to the Knight Agreement and $0.5 million of cost of revenue pursuant to the AstraZeneca Termination Agreement.

AstraZeneca

In June 2015, the Company entered into a termination agreement with AstraZeneca, or the Termination Agreement, pursuant to which the Company remains liable to pay AstraZeneca license fees for (i) future royalties at a royalty rate of 10% of net sales of tenapanor or other NHE3 products by the Company or its licensees, and (ii) 20% of non-royalty revenue received from a new collaboration partner should the Company elect to license, or otherwise provide rights to develop and commercialize tenapanor or another NHE3 inhibitor, up to a maximum of $75.0 million in aggregate for (i) and (ii). To date in aggregate, the Company has recognized $9.9 million of the $75.0 million, recorded as cost of revenue comprising (i) $6.0 million and $2.4 million related to the KHK Agreement and Fosun Agreement, respectively, recorded in 2017 (ii) $1.0 million related to the KHK Agreement associated with a future milestone which the Company believes is not materially at risk for which the Company recorded an increase in current liabilities in the period ended March 31, 2018 reflecting the future payable to AstraZeneca and (iii) $0.5 million related to the Knight Agreement recorded in the period ended March 31, 2018.