Loan payable Long-term Debt Number of awards granted (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period Commission on sale of stock per agreement (percent) Stock Issuance Cost, Commission, Percent Stock Issuance Cost, Commission, Percent Leases Lessee, Operating Leases [Text Block] Document Type Document Type Fair Value Disclosures [Abstract] Fair Value Disclosures [Abstract] Comprehensive loss: Comprehensive Income (Loss), Net of Tax, Attributable to Parent [Abstract] Long-term investments: Long-term Investments [Abstract] Deferred revenue Increase (Decrease) in Deferred Revenue Contingencies Commitments and Contingencies Disclosure [Text Block] Number of options granted Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross Amortization of (discount) premium on investment securities Accretion (Amortization) of Discounts and Premiums, Investments Non-cash interest associated with debt discount accretion Amortization of Debt Discount (Premium) Share-based Payment Arrangement, Expensed and Capitalized, Amount [Table] Share-based Payment Arrangement, Expensed and Capitalized, Amount [Table] Lease costs Lease, Cost [Abstract] Short-term investments, Fair Value Debt Securities, Available-for-sale Total operating expenses Costs and Expenses Collaborative development revenue Collaborative Development [Member] Collaborative Development [Member] Equity Components [Axis] Equity Components [Axis] Additional default interest rate Debt Instrument, Interest Rate On Default, Percentage Percentage of additional default interest rate on the event of default. Share-based Payment Arrangement [Abstract] Share-based Payment Arrangement [Abstract] Total cash equivalents and investments, Gross Unrealized Gains Investments And Cash, Accumulated Gross Unrealized Gain Investments And Cash, Accumulated Gross Unrealized Gain Exit Fee derivative Other Contract [Member] Minimum Minimum [Member] Level 3 Fair Value, Inputs, Level 3 [Member] Summary of Additional Details of Leases Schedule of Additional Details of Leases [Table Text Block] The tabular disclosure of additional details of the leases. Final fee due upon maturity, acceleration, prepayment, or termination (percent) Debt Instrument, Fee Due Upon Maturity, Acceleration, Prepayment, Termination, Percentage Debt Instrument, Fee Due Upon Maturity, Acceleration, Prepayment, Termination, Percentage AstraZeneca Astrazeneca [Member] Represents information pertaining to AstraZeneca. Current portion of operating lease liability Current portion of lease liabilities Current portion of operating lease liability Operating Lease, Liability, Current Term of payment of license fee, first installment Term Of Payment Of License Fee, First Installment Term of payment of first installment fee. Fair value analysis, percentage change in probability of occurrence Fair Value Sensitivity Analysis, Change In Probability Of Occurrence, Percentage Fair Value Sensitivity Analysis, Change In Probability Of Occurrence, Percentage Statistical Measurement [Domain] Statistical Measurement [Domain] Liabilities and stockholders’ equity Liabilities and Equity [Abstract] Share-based Compensation Arrangement by Share-based Payment Award [Line Items] Share-based Compensation Arrangement by Share-based Payment Award [Line Items] Number of separate collaborative agreements Number Of Separate Collaborative Agreements Number of separate collaborative agreements. Derivative Liability Derivative Instruments and Hedging Activities Disclosure [Text Block] Asset-backed securities Asset-backed Securities [Member] Entity Interactive Data Current Entity Interactive Data Current Total cash equivalents and investments, Amortized Cost Investments and Cash Revenues: Revenues [Abstract] Security Exchange Name Security Exchange Name Fair Value Measurements Fair Value Disclosures [Text Block] Operating activities Net Cash Provided by (Used in) Operating Activities [Abstract] Stockholders' Equity Stockholders' Equity Note Disclosure [Text Block] Second installment of upfront license fees Collaboration And Licensing Agreements, Upfront License Fees, Second Installment Collaboration And Licensing Agreements, Upfront License Fees, Second Installment At-the-market offering At Market Offering [Member] Represents information relating to At the market offering. Amortization of deferred compensation for services Amortization of Deferred Charges Loss from operations Operating Income (Loss) Total current liabilities Liabilities, Current Additional paid-in capital Additional Paid in Capital, Common Stock Entity Registrant Name Entity Registrant Name Derivative [Table] Derivative [Table] Schedule of Changes in Deferred Revenue Contract with Customer, Contract Asset, Contract Liability, and Receivable [Table Text Block] Statement of Stockholders' Equity [Abstract] Statement of Stockholders' Equity [Abstract] Weighted-average discount rate Operating Lease, Weighted Average Discount Rate, Percent Assets: Assets, Fair Value Disclosure [Abstract] Prepaid expenses and other current assets Prepaid Expense and Other Assets, Current Less: Unaccreted value of final fee Debt Instrument, Fee Amount Fosun Agreement License Agreement Development Commercialization Distribution In China [Member] Agreement for the development, commercialization and distribution of tenapanor in China. The Fosun Agreement. Commitments and contingencies (Note 11) Commitments and Contingencies Assets Assets [Abstract] Closing fee Debt Instrument, Closing Fee Debt Instrument, Closing Fee Non-current deferred revenue Change In Contract With Customer Liability, Noncurrent, Rollforward [Roll Forward] Change In Contract With Customer Liability, Noncurrent, Rollforward Summary of Total Unrecognized Stock-Based Compensation Expense, Net of Estimated Forfeitures Share-based Payment Arrangement, Nonvested Award, Cost [Table Text Block] Entity Address, State or Province Entity Address, State or Province Cash paid for operating leases Operating Lease, Payments Accounts payable Accounts Payable, Current Change in derivative liabilities Increase (Decrease) in Derivative Liabilities Research and development Research and Development Expense [Member] 2017 KKC Agreement License Agreement Development Commercialization Distribution In Japan [Member] Agreement for the development, commercialization and distribution of tenapanor in Japan. The 2017 KKC Agreement. Accumulated deficit Retained Earnings (Accumulated Deficit) Right-of-use assets, net Right-of-use assets Operating Lease, Right-of-Use Asset Entity Incorporation, State or Country Code Entity Incorporation, State or Country Code Accounts receivable Accounts Receivable, after Allowance for Credit Loss, Current Total undiscounted operating lease payments Lessee, Operating Lease, Liability, to be Paid Other-than-temporary impairment Other-than-temporary Impairment Loss, Debt Securities, Available-for-sale Long-term investments, Gross Unrealized Gains Long Term Investments, Accumulated Gross Unrealized Gain Long Term Investments, Accumulated Gross Unrealized Gain Cover Entity Addresses [Line Items] Debt Instrument, Redemption, Period [Domain] Debt Instrument, Redemption, Period [Domain] Short-term investments, Gross Unrealized Losses Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax Summary of Fair Value of Financial Assets and Liabilities Measured or Disclosed on a Recurring Basis Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis [Table Text Block] Unrecognized Compensation Expense Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Amount Sale of Stock [Axis] Sale of Stock [Axis] Entity Address, Postal Zip Code Entity Address, Postal Zip Code Agreed amount for exit fee upon change of control or regulatory approval Derivative Liability, Notional Amount Total cash equivalents and short-term investments, Fair Value Cash Cash Equivalents And Short Term Investments Fair Value Disclosure Cash, cash equivalents and short term investments fair value disclosure. After first anniversary through second anniversary of closing date Debt Instrument, Redemption, Period Two [Member] Fair Value by Liability Class [Domain] Fair Value by Liability Class [Domain] Beginning balance (shares) Ending balance (shares) Shares, Outstanding Preferred stock, $0.0001 par value; 5,000,000 shares authorized; no shares issued and outstanding as of March 31, 2021 and December 31, 2020, respectively. Preferred Stock, Value, Issued KKC Kyowa Kirin Co. Ltd [Member] Represents the information pertaining to Kyowa Kirin Co., Ltd. Document Transition Report Document Transition Report Debt Instrument, Redemption, Period [Axis] Debt Instrument, Redemption, Period [Axis] Common stock, par value (in dollars per share) Common Stock, Par or Stated Value Per Share Title of Individual [Axis] Title of Individual [Axis] Investment in continuous unrealized loss position for more than one year Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss Arrangements and Non-arrangement Transactions [Domain] Collaborative Arrangement and Arrangement Other than Collaborative [Domain] Stock-based Compensation [Line Items] Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items] Prepayment due Increases to amounts invoiced, for which cash has not yet been received Contract With Customer, Liability, Increase For Amounts Invoiced Contract With Customer, Liability, Increase For Amounts Invoiced Numerator: Net Income (Loss) Attributable to Parent [Abstract] 2019 KKC Agreement Research Collaboration And Option Agreement [Member] Pertaining to the research collaboration and option agreement for research associated with identifying two pre-clinical compounds. The 2019 KKC AGreement. Liability Class [Axis] Liability Class [Axis] Potential commercialization milestones Collaborative Arrangement, Potential Commercialization Milestones Collaborative Arrangement, Potential Commercialization Milestones Term loan face amount Debt Instrument, Face Amount Stock-based compensation APIC, Share-based Payment Arrangement, Increase for Cost Recognition Level 2 Fair Value, Inputs, Level 2 [Member] Potential development milestones Collaborative Arrangement, Potential Development Milestones Collaborative Arrangement, Potential Development Milestones Document Quarterly Report Document Quarterly Report Liabilities: Liabilities, Fair Value Disclosure [Abstract] Total revenues Revenue Revenue from Contract with Customer, Excluding Assessed Tax Measurement Frequency [Domain] Measurement Frequency [Domain] Asset Class [Domain] Asset Class [Domain] General and administrative General and Administrative Expense [Member] Purchase price (in dollars per share) Share Price Assets, fair value Assets, Fair Value Disclosure Supplementary disclosure of non-cash activities: Cash Flow, Noncash Investing and Financing Activities Disclosure [Abstract] Deferred revenue Beginning balance Ending balance Contract with Customer, Liability, Current Statement [Line Items] Statement [Line Items] Derivative Contract [Domain] Derivative Contract [Domain] Shares used in computing net loss per share - diluted Weighted average common shares outstanding - diluted Weighted Average Number of Shares Outstanding, Diluted Class of Stock [Domain] Class of Stock [Domain] Net loss per share - basic (in dollars per share) Earnings Per Share, Basic Number of segments Number of Operating Segments Entity File Number Entity File Number Collaborative Arrangement and Arrangement Other than Collaborative [Table] Collaborative Arrangement and Arrangement Other than Collaborative [Table] Debt Disclosure [Abstract] Debt Disclosure [Abstract] Upfront payment received Proceeds from License Fees Received Weighted-average remaining life (years) Operating Lease, Weighted Average Remaining Lease Term Statement [Table] Statement [Table] Statistical Measurement [Axis] Statistical Measurement [Axis] Non-cash lease expense Operating Lease, Right-of-Use Asset, Amortization Expense Preferred stock, shares issued Preferred Stock, Shares Issued Net cash provided by financing activities Net Cash Provided by (Used in) Financing Activities Percentage of royalty revenue Percentage of Royalty Revenue Represents percentage of royalty revenue. Stock-based compensation expense Share-based Payment Arrangement, Expense Cash, Cash Equivalents and Short-Term Investments Cash, Cash Equivalents, and Short-term Investments [Text Block] Issuance of common stock under employee stock purchase plan Proceeds from ESPP Stock Issued During Period, Value, Employee Stock Purchase Plan Counterparty Name [Axis] Counterparty Name [Axis] Common stock, $0.0001 par value; 300,000,000 shares authorized; 98,688,577 and 93,599,975 shares issued and outstanding as of March 31, 2021 and December 31, 2020, respectively. Common Stock, Value, Issued Long-term investments Long-term Investments Entity Small Business Entity Small Business Document Fiscal Year Focus Document Fiscal Year Focus Undiscounted cash payment obligations Lessee, Operating Lease, Liability, Payment, Due [Abstract] Commercial paper Commercial Paper [Member] Cash and Cash Equivalents [Axis] Cash and Cash Equivalents [Axis] Entity Current Reporting Status Entity Current Reporting Status Change in estimated fair value of derivative liability Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Gain (Loss) Included in Earnings Borrowing Debt Disclosure [Text Block] Fair Value Hierarchy and NAV [Domain] Fair Value Hierarchy and NAV [Domain] Proceeds from issuance of common stock in at-the-market offering, net of issuance costs Proceeds from Issuance of Common Stock Cost of revenue Cost of Revenue Prior to first anniversary of closing date Debt Instrument, Redemption, Period One [Member] Proceeds from maturities and redemptions of investments Proceeds from Sale and Maturity of Debt Securities, Available-for-sale Amendment Flag Amendment Flag Schedule of Computation of Net Loss Per Common Share Schedule of Earnings Per Share, Basic and Diluted [Table Text Block] Schedule of Long-term Debt Instruments [Table] Schedule of Long-term Debt Instruments [Table] Fair value of Exit Fee derivative liability, beginning Fair value of Exit Fee derivative liability, ending Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability Value Knight Knight Therapeutics Inc [Member] Represents information pertaining to Knight Therapeutics Inc. Collaboration and Licensing Agreements Collaborative Arrangement Disclosure [Text Block] Investing activities Net Cash Provided by (Used in) Investing Activities [Abstract] Common stock, shares issued Common Stock, Shares, Issued Cash and cash equivalents Cash and cash equivalents, Amortized Cost Cash and Cash Equivalents, at Carrying Value Fair Value Measurements Fair Value Measurement, Policy [Policy Text Block] Cash Cash Equivalents And Short Term Investments [Table] Cash Cash Equivalents And Short Term Investments [Table] Cash and cash equivalents and short term investments. Total operating lease liabilities Operating Lease, Liability Net cash used in operating activities Net Cash Provided by (Used in) Operating Activities Subsidiary or Equity Method Investee, Sale of Stock by Subsidiary or Equity Investee [Table] Subsidiary or Equity Method Investee, Sale of Stock by Subsidiary or Equity Investee [Table] Entity Central Index Key Entity Central Index Key Commercial paper Commercial Paper, Not Included with Cash and Cash Equivalents [Member] Measurement Frequency [Axis] Measurement Frequency [Axis] Accounts receivable Increase (Decrease) in Accounts Receivable Short-term investments Debt Securities, Available-for-sale, Current Debt Instrument [Line Items] Debt Instrument [Line Items] Derivative Instrument [Axis] Derivative Instrument [Axis] Financial Instruments [Domain] Financial Instruments [Domain] Total stockholders’ equity Beginning balance Ending balance Stockholders' Equity Attributable to Parent After second anniversary to maturity date Debt Instrument, Redemption, Period Three [Member] Potential development and commercialization milestones Collaborative Arrangement, Potential Development And Commercialization Milestones Represents the amount of future development and commercialization milestone under collaborative arrangements. Total liabilities and stockholders’ equity Liabilities and Equity Accumulated other comprehensive income Accumulated Other Comprehensive Income (Loss), Net of Tax Entity Address, City or Town Entity Address, City or Town Accrued compensation and benefits Employee-related Liabilities, Current Subsequent Events Subsequent Events [Text Block] Collaboration and Licensing Agreements Collaboration and Licensing Agreements n/a Fair Value Hierarchy and NAV [Axis] Fair Value Hierarchy and NAV [Axis] RSUs Restricted Stock Units (RSUs) [Member] Operating lease expense Operating Lease, Cost Right-of-use assets and lease liabilities Assets and Liabilities, Lessee [Abstract] General and administrative General and Administrative Expense Financial Instrument [Axis] Financial Instrument [Axis] Short-term investments, Amortized Cost Debt Securities, Available-for-sale, Amortized Cost Anti-dilutive securities not included in computation of diluted net loss per share Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount Short-term investments, Gross Unrealized Gains Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax Statement of Cash Flows [Abstract] Statement of Cash Flows [Abstract] Equity Component [Domain] Equity Component [Domain] Total cash equivalents and short-term investments, Gross Unrealized Gains Cash Cash Equivalents And Short Term Investments Gross Unrealized Gains Cash, cash equivalents and short term investments gross unrealized gains. Cash, cash equivalents and marketable securities Total cash equivalents and short-term investments, Amortized Cost Cash, Cash Equivalents, and Short-term Investments Income Statement Location [Axis] Income Statement Location [Axis] Current deferred revenue Change In Contract With Customer Liability, Current, Rollforward [Roll Forward] Change In Contract With Customer Liability, Current, Rollforward Loan payable, net of current portion Loans Payable, Noncurrent Entity Common Stock, Shares Outstanding Entity Common Stock, Shares Outstanding Income Statement Location [Domain] Income Statement Location [Domain] Cash Cash [Member] Financing activities Net Cash Provided by (Used in) Financing Activities [Abstract] Property and equipment, net Property, Plant and Equipment, Net Entity Tax Identification Number Entity Tax Identification Number Stockholders' Equity Note [Abstract] Stockholders' Equity Note [Abstract] Equity Incentive Plans Share-based Payment Arrangement [Text Block] Net loss Net loss Net Income (Loss) Attributable to Parent Summary of Lease Costs Lease, Cost [Table Text Block] Fair value analysis, effect on fair value based on 10% change in probability of occurrence Fair Value Sensitivity Analysis, Ten Percent Change In Probability Of Occurrence, Effect On Valuation Fair Value Sensitivity Analysis, Ten Percent Change In Probability Of Occurrence, Effect On Valuation Changes in operating assets and liabilities: Increase (Decrease) in Operating Capital [Abstract] Short-term investments Debt Securities, Available-for-sale, Fair Value to Amortized Cost [Abstract] Remainder of 2021 Lessee, Operating Lease, Liability, to be Paid, Remainder of Fiscal Year Issuance of common stock for services (shares) Stock Issued During Period, Shares, Issued for Services Other assets Other Assets, Noncurrent Plan Name [Axis] Plan Name [Axis] Thereafter Lessee, Operating Lease, Liability, To Be Paid, After Current Fiscal Year Lessee, Operating Lease, Liability, To Be Paid, After Current Fiscal Year Issuance of common stock in at-the-market offering Stock Issued During Period, Value, New Issues Leases [Abstract] Leases [Abstract] Cash and cash equivalents, Fair Value Cash and Cash Equivalents, Fair Value Disclosure Issuance of common stock upon vesting of restricted stock units (shares) Stock Issued During Period, Shares, Restricted Stock Award, Net of Forfeitures Total assets Assets Long-term Debt, Type [Axis] Long-term Debt, Type [Axis] Total current assets Assets, Current Current Fiscal Year End Date Current Fiscal Year End Date Cash Cash Equivalents And Short Term Investments [Line Items] Cash Cash Equivalents And Short Term Investments [Line Items] Cash and cash equivalents and short term investments. Operating expenses: Operating Expenses [Abstract] Earnings Per Share [Abstract] Earnings Per Share [Abstract] Organization and Basis of Presentation Organization, Consolidation, Basis of Presentation, Business Description and Accounting Policies [Text Block] Title of 12(b) Security Title of 12(b) Security Maximum potential payment per agreement Collaborative Arrangement, Potential Payment Per Termination Agreement, Maximum Collaborative Arrangement, Potential Payment Per Termination Agreement, Maximum Upfront license fees Collaboration And Licensing Agreements, Upfront License Fees Collaboration And Licensing Agreements, Upfront License Fees Weighted-average grant-date estimated fair value of options granted (in dollars per share) Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Weighted Average Grant Date Fair Value Long-term investments, Amortized Cost Long Term Investments, Amortized Cost Long Term Investments, Amortized Cost Co-Headquarter Other Address [Member] Stockholders’ equity: Stockholders' Equity Attributable to Parent [Abstract] Cash and Cash Equivalents [Abstract] Cash and Cash Equivalents [Abstract] Document Fiscal Period Focus Document Fiscal Period Focus U.S. government-sponsored agency bonds US Government Corporations and Agencies Securities [Member] Interest expense Interest Expense Subsidiary, Sale of Stock [Line Items] Subsidiary, Sale of Stock [Line Items] Product and Service [Axis] Product and Service [Axis] Total liabilities Liabilities Deferred revenue, non-current Beginning balance Ending balance Contract with Customer, Liability, Noncurrent Total cash equivalents and investments, Fair Value Investments And Cash, Fair Value Disclosure Investments And Cash, Fair Value Disclosure Supplementary disclosure of cash flow information: Supplemental Cash Flow Information [Abstract] Term of agreement Term Of Agreement Term of agreement. Average Remaining Vesting Period (Years) Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Period for Recognition Issuance of common stock under employee stock purchase plan (shares) Number of shares issued under ESPP Stock Issued During Period, Shares, Employee Stock Purchase Plans Imputed interest expenses Lessee, Operating Lease, Liability, Undiscounted Excess Amount Entity Filer Category Entity Filer Category Summary of Stock-Based Compensation Expense Recognized Share-based Payment Arrangement, Expensed and Capitalized, Amount [Table Text Block] Common Stock Common Stock [Member] Products and Services [Domain] Product and Service [Domain] Commitments and Contingencies Disclosure [Abstract] Commitments and Contingencies Disclosure [Abstract] Level 1 Fair Value, Inputs, Level 1 [Member] Prepayment premium (as a percent) Debt Instrument, Prepayment Fee, Percentage The percentage of fee payable on prepayment of debt. Loan payable, current portion Loan payable, current portion Loans Payable, Current Fair Value, Recurring and Nonrecurring [Table] Fair Value, Recurring and Nonrecurring [Table] Accounts payable Increase (Decrease) in Accounts Payable Payments made per agreement Payments of Uncharged License Fees Represents the cash outflow from payments of uncharged license fees. Derivative liability for Exit Fee Exit Fee derivative liability Derivative Financial Instruments, Liabilities [Member] Issuance of common stock in at-the-market offering (shares) Stock Issued During Period, Shares, New Issues Threshold percentage of net sales for tiered royalties Threshold Percentage of Sales For Tiered Royalties Represents the threshold percentage of net sales for tiered royalties. Additional Paid-In Capital Additional Paid-in Capital [Member] U.S. treasury notes US Treasury Notes Securities [Member] Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Table] Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Table] PRSUs Performance Based Restricted Stock Units [Member] This member stands for performance-based restricted stock units. Money market funds Money Market Funds [Member] Common stock Common Class A [Member] Accrued and other liabilities Increase (Decrease) in Accrued Liabilities Asset Class [Axis] Asset Class [Axis] Adjustments to reconcile net loss to net cash used in operating activities: Adjustments to Reconcile Net Income (Loss) to Cash Provided by (Used in) Operating Activities [Abstract] Issuance of common stock upon exercise of options (shares) Number of options exercised Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period Net decrease in cash and cash equivalents Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Period Increase (Decrease), Including Exchange Rate Effect Other income (expense), net Nonoperating Income (Expense) Unrealized (losses) gains on available-for-sale securities Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, Net of Tax, Portion Attributable to Parent Common stock, shares outstanding Common Stock, Shares, Outstanding Summary of Undiscounted Cash Payment Obligations for Operating Lease Liabilities Lessee, Operating Lease, Liability, Maturity [Table Text Block] Stock options Share-based Payment Arrangement, Option [Member] Basis of Presentation Basis of Accounting, Policy [Policy Text Block] Shares used in computing net loss per share - basic Weighted average common shares outstanding - basic Weighted Average Number of Shares Outstanding, Basic Loss before provision for income taxes Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest Research and development Research and Development Expense Subsequent Events [Abstract] Subsequent Events [Abstract] Sale of Stock [Domain] Sale of Stock [Domain] Fosun Pharma Shanghai Fosun Pharmaceutical Industrial Development [Member] Represents Shanghai Fosun Pharmaceutical Industrial Development. Common stock, shares authorized Common Stock, Shares Authorized Net proceeds from options exercised Proceeds from Stock Options Exercised Plan Name [Domain] Plan Name [Domain] Entity Addresses, Address Type [Axis] Entity Addresses, Address Type [Axis] Entity Addresses [Table] Entity Addresses [Table] Cash paid for interest Interest Paid, Excluding Capitalized Interest, Operating Activities Future payment obligations Long-term Debt, Fiscal Year Maturity [Abstract] Knight Agreement License Agreement Development Commercialization Distribution In Canada [Member] Agreement for the development, commercialization and distribution fo tenapanor in Canada. The Knight Agreement. Right-of-use assets obtained in exchange for lease obligations Right-of-Use Asset Obtained in Exchange for Operating Lease Liability Class of Stock [Axis] Class of Stock [Axis] Collaborative Arrangement and Arrangement Other than Collaborative [Line Items] Collaborative Arrangement and Arrangement Other than Collaborative [Line Items] Provision for income taxes Income Tax Expense (Benefit) Total cash equivalents and short-term investments, Gross Unrealized Losses Cash Cash Equivalents And Short Term Investments Gross Unrealized Losses Cash, cash equivalents and short term investments gross unrealized losses. Accrued compensation and benefits Increase (Decrease) in Employee Related Liabilities Cash paid for income taxes Income Taxes Paid, Net Income Statement [Abstract] Income Statement [Abstract] Cash and cash equivalents at beginning of period Cash and cash equivalents at end of period Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents Accumulated Other Comprehensive (Loss) Income AOCI Attributable to Parent [Member] Schedule of Future Debt Payment Obligations Schedule of Maturities of Long-term Debt [Table Text Block] Title of Individual [Domain] Title of Individual [Domain] Liabilities, fair value Financial and Nonfinancial Liabilities, Fair Value Disclosure Operating lease liability, net of current portion Operating lease liability, net of current portion Operating Lease, Liability, Noncurrent Prepaid expenses and other assets Increase (Decrease) in Prepaid Expense and Other Assets Net loss per share - diluted (in dollars per share) Earnings Per Share, Diluted Local Phone Number Local Phone Number Schedule of Securities Classified as Cash, Cash Equivalents and Investments Cash, Cash Equivalents and Investments [Table Text Block] Derivative Instruments and Hedging Activities Disclosure [Abstract] Derivative Instruments and Hedging Activities Disclosure [Abstract] Collaborative Arrangement and Arrangement Other than Collaborative [Axis] Collaborative Arrangement and Arrangement Other than Collaborative [Axis] Accrued expenses and other current liabilities Accrued Liabilities and Other Liabilities Less: Unamortized discount and debt issuance costs Debt Instrument, Unamortized Discount (Premium) and Debt Issuance Costs, Net Long-term investments, Fair Value Long Term Investments, Fair Value Long Term Investments, Fair Value Cash and cash equivalents: Cash and Cash Equivalents, at Carrying Value [Abstract] Use of Estimates Use of Estimates, Policy [Policy Text Block] ESPP Employee Stock Purchase Plan [Member] Employee Stock Purchase Plan [Member] Derivative [Line Items] Derivative [Line Items] Schedule of Changes in Fair Value of Derivative Liability Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Table Text Block] Current assets: Assets, Current [Abstract] Address Type [Domain] Address Type [Domain] Change in Fair Value of Derivative Liability Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] Total repayment obligations Long-term Debt, Gross Depreciation expense Depreciation Entity Address, Address Line One Entity Address, Address Line One Entity Address, Address Line Two Entity Address, Address Line Two Weighted-average sales price per share Sale Of Stock, Weighted-Average Price Per Share Sale Of Stock, Weighted-Average Price Per Share Deferred revenue Contract with Customer, Liability Long-term investments, Gross Unrealized Losses Long Term Investments, Accumulated Gross Unrealized Loss Long Term Investments, Accumulated Gross Unrealized Loss Entity Emerging Growth Company Entity Emerging Growth Company Issuance of common stock upon exercise of options Stock Issued During Period, Value, Stock Options Exercised Comprehensive loss Comprehensive Income (Loss), Net of Tax, Attributable to Parent AstraZeneca Termination Agreement AstraZeneca Termination Agreement [Member] AstraZeneca Termination Agreement Preferred stock, par value (in dollars per share) Preferred Stock, Par or Stated Value Per Share Operating lease liabilities Increase (Decrease) In Operating Lease Liability Increase (Decrease) In Operating Lease Liability Licensing revenue License [Member] Award Type [Axis] Award Type [Axis] Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] Counterparty Name [Domain] Counterparty Name [Domain] Purchases of property and equipment Payments to Acquire Property, Plant, and Equipment City Area Code City Area Code Amortization of deferred financing costs Amortization of Debt Issuance Costs Preferred stock, shares authorized Preferred Stock, Shares Authorized Revenue recognized Decreases due to revenue recognized in the period for which cash has been received Contract with Customer Liability Revenue Recognized Cash Received Amount of revenue recognized that was previously included in balance of obligation to transfer good or service to customer for which consideration from customer has been received. Document Period End Date Document Period End Date Purchases of investments Payments to Acquire Short-term Investments Accumulated Deficit Retained Earnings [Member] Preferred stock, shares outstanding Preferred Stock, Shares Outstanding Contingent liabilities Loss Contingency Accrual Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] Net cash provided by (used in) investing activities Net Cash Provided by (Used in) Investing Activities Board of directors Director [Member] Schedule of Share-based Compensation Arrangements by Share-based Payment Award [Table] Schedule of Share-based Compensation Arrangements by Share-based Payment Award [Table] Award Type [Domain] Award Type [Domain] Corporate bonds Corporate Debt Securities [Member] Trading Symbol Trading Symbol Percentage of non-royalty revenue Percentage of non royalty revenue Represents percentage of non-royalty revenue. Interest-only payment extension term (in months) Debt Instrument, Interest Payment Extension Term Debt Instrument, Interest Payment Extension Term Denominator: Weighted Average Number of Shares Outstanding Reconciliation [Abstract] Additional details Lessee, Operating Lease, Description [Abstract] Long-term Debt, Type [Domain] Long-term Debt, Type [Domain] Proceeds from issuance of common stock under equity incentive and stock purchase plans Proceeds, Issuance of Shares, Share-based Payment Arrangement, Including Option Exercised Stock-based compensation Share-based Payment Arrangement, Noncash Expense Net Loss Per Share Earnings Per Share [Text Block] Cover [Abstract] Cover [Abstract] Organization, Consolidation and Presentation of Financial Statements [Abstract] Organization, Consolidation and Presentation of Financial Statements [Abstract] Total cash equivalents and investments, Gross Unrealized Losses Investments And Cash, Accumulated Gross Unrealized Loss Investments And Cash, Accumulated Gross Unrealized Loss Product supply revenue Product Supply Revenue [Member] Product Supply Revenue Current liabilities: Liabilities, Current [Abstract] Entity Shell Company Entity Shell Company Closing fee (percent) Debt Instrument, Closing Fee, Percentage Debt Instrument, Closing Fee, Percentage Recurring Fair Value, Recurring [Member] Maximum aggregate offering price Maximum Aggregate Offering Price Amount of maximum aggregate offering price. First installment of upfront license fees Collaboration And Licensing Agreements, Upfront License Fees, First Installment Collaboration And Licensing Agreements, Upfront License Fees, First Installment Other revenue Other Product Or Services Revenue [Member] Represents the information pertaining to revenues from other product or services. Development milestones received Collaborative Arrangement Development Milestones Payment Received The amount of development milestone payment received to date. Recent Accounting Pronouncements New Accounting Pronouncements, Policy [Policy Text Block] Cash and Cash Equivalents [Domain] Cash and Cash Equivalents [Domain] Statement of Financial Position [Abstract] Statement of Financial Position [Abstract] Term Loan Loans Payable [Member]