Supplementary disclosure of cash flow information: Supplemental Cash Flow Information [Abstract] Customer [Domain] Customer [Domain] Work in process Inventory, Work in Process, Gross Vested (shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period Fair Value Hierarchy and NAV [Domain] Fair Value Hierarchy and NAV [Domain] Net loss Net loss Net Income (Loss) Attributable to Parent Right-of-use assets Right-of-use assets Operating Lease, Right-of-Use Asset Short-term investments Debt Securities, Available-for-sale, Current Preferred stock, shares outstanding Preferred Stock, Shares Outstanding Additional default interest rate Debt Instrument, Interest Rate On Default, Percentage Percentage of additional default interest rate on the event of default. Accrued compensation and benefits Employee-related Liabilities, Current Income Statement Location [Axis] Income Statement Location [Axis] Receivable Type [Axis] Receivable Type [Axis] Statistical Measurement [Domain] Statistical Measurement [Domain] Summary of Additional Details of Leases Schedule of Additional Details of Leases [Table Text Block] The tabular disclosure of additional details of the leases. Schedule of Future Debt Payment Obligations Schedule of Maturities of Long-term Debt [Table Text Block] Security Exchange Name Security Exchange Name Entity Incorporation, State or Country Code Entity Incorporation, State or Country Code Forfeited (in dollars per share) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeitures, Weighted Average Grant Date Fair Value Revenue from Contract with Customer [Abstract] Schedule of Changes in Deferred Revenue Contract with Customer, Contract Asset, Contract Liability, and Receivable [Table Text Block] Additional paid-in capital Additional Paid in Capital, Common Stock Options forfeited (shares) Share-based Compensation Arrangement by Share-based Payment Award, Options, Forfeitures in Period Weighted-average remaining life (years) Operating Lease, Weighted Average Remaining Lease Term Other assets Other Assets, Noncurrent Schedule of Share-based Compensation Arrangements by Share-based Payment Award [Table] Schedule of Share-based Compensation Arrangements by Share-based Payment Award [Table] Net decrease in cash and cash equivalents Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Period Increase (Decrease), Including Exchange Rate Effect Entity File Number Entity File Number Change in Fair Value of Derivative Liability Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] Stock-based compensation APIC, Share-based Payment Arrangement, Increase for Cost Recognition Changes in estimated fair value Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Gain (Loss) Included in Earnings Subsequent Event Type [Domain] Subsequent Event Type [Domain] Organization, Consolidation and Presentation of Financial Statements [Abstract] Organization, Consolidation and Presentation of Financial Statements [Abstract] Anti-dilutive securities not included in computation of diluted net loss per share Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount Weighted-average discount rate Operating Lease, Weighted Average Discount Rate, Percent Schedule of Inventory Schedule of Inventory, Current [Table Text Block] Research and development Research and Development Expense [Member] Sale of Stock [Axis] Sale of Stock [Axis] Liability Class [Axis] Liability Class [Axis] Subsequent Events [Abstract] Subsequent Events [Abstract] Granted (in dollars per share) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value Upfront payment received Proceeds from License Fees Received Title of Individual [Domain] Title of Individual [Domain] Award Type [Domain] Award Type [Domain] Local Phone Number Local Phone Number Assets Assets [Abstract] Gross-to-net sales accruals Beginning balance Ending balance Contract With Customer, Gross To Net Sales Accruals Contract With Customer, Gross To Net Sales Accruals Options exercisable (shares) Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Number Fee receivable for reduction in royalty rate Collaborative Arrangement, Fee Receivable For Reduction In Royalty Rate Collaborative Arrangement, Fee Receivable For Reduction In Royalty Rate Derivative Liability Derivative Instruments and Hedging Activities Disclosure [Text Block] Other Fees, Copay and Returns Contract With Customer, Other Fees, Copay And Returns [Member] Contract With Customer, Other Fees, Copay And Returns KKC Kyowa Kirin Co. Ltd [Member] Represents the information pertaining to Kyowa Kirin Co., Ltd. Granted (shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period Loan agreement covenant, net product revenue as percentage of outstanding loan balance, minimum Loan Agreement, Covenant, Net Product Revenue As Percentage Of Outstanding Loan Balance, Minimum Loan Agreement, Covenant, Net Product Revenue As Percentage Of Outstanding Loan Balance, Minimum Concentration risk (percent) Concentration Risk, Percentage Preferred stock, $0.0001 par value; 5,000,000 shares authorized; no shares issued and outstanding as of March 31, 2022 and December 31, 2021, respectively. Preferred Stock, Value, Issued Proceeds from issuance of common stock under equity incentive and stock purchase plans Proceeds, Issuance of Shares, Share-based Payment Arrangement, Including Option Exercised Options outstanding balance, beginning (shares) Options outstanding balance, ending (shares) Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number Accumulated Deficit Retained Earnings [Member] Remaining funding based on milestone achievement Remaining Funding Based On Conditional Milestone Achievement Remaining Funding Based On Conditional Milestone Achievement Debt Instrument [Axis] Debt Instrument [Axis] Potential commercialization milestones Collaborative Arrangement, Potential Commercialization Milestones Collaborative Arrangement, Potential Commercialization Milestones Prepaid expenses and other assets Increase (Decrease) in Prepaid Expense and Other Assets Contingencies Commitments and Contingencies Disclosure [Text Block] Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] Accounts receivable Increase (Decrease) in Accounts Receivable Right-of-use assets obtained in exchange for lease obligations Right-of-Use Asset Obtained in Exchange for Operating Lease Liability Derivative Instruments and Hedging Activities Disclosure [Abstract] Derivative Instruments and Hedging Activities Disclosure [Abstract] Commitments and Contingencies Disclosure [Abstract] Commitments and Contingencies Disclosure [Abstract] Closing fee Debt Instrument, Closing Fee Amount Debt Instrument, Closing Fee Amount Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Table] Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Table] Deferred revenue Increase (Decrease) in Deferred Revenue Total cash equivalents and investments, Gross Unrealized Losses Cash Cash Equivalents And Investments Gross Unrealized Losses Cash, cash equivalents and investments gross unrealized losses. Number of segments Number of Operating Segments Stock-based Compensation [Line Items] Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items] Net loss per common share - basic (in dollars per share) Earnings Per Share, Basic 2025 Lessee, Operating Lease, Liability, to be Paid, Year Three Percentage of royalty revenue Percentage of Royalty Revenue Represents percentage of royalty revenue. Product Revenue, Net Revenue from Contract with Customer [Text Block] Outstanding balance, beginning (shares) Outstanding balance, ending (shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number 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 Raw materials Inventory, Raw Materials, Gross Number of RSUs Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward] Cardinal Health Cardinal Health [Member] Cardinal Health Commercial customers Accounts Receivable, Commercial Customer [Member] Accounts Receivable, Commercial Customer Commercial paper Commercial Paper [Member] Cash paid for operating lease Operating Lease, Payments Proceeds from sale of equipment Proceeds from Sale of Machinery and Equipment Principal outstanding Long-term Debt, Gross Long-term Debt, Gross After first anniversary through second anniversary of closing date Debt Instrument, Redemption, Period Two [Member] Gross To Net Sales Accrual And Reserve Classification [Axis] Gross To Net Sales Accrual And Reserve Classification [Axis] Gross To Net Sales Accrual And Reserve Classification IBSRELA Product, IBSRELA [Member] Product, IBSRELA Proceeds from 2022 Loan, net of issuance costs Proceeds from Issuance of Secured Debt Plan Name [Axis] Plan Name [Axis] Assets, Fair Value Disclosure [Abstract] Assets, Fair Value Disclosure [Abstract] Long-term debt Long-term Debt Assets, fair value Assets, Fair Value Disclosure Level 1 Fair Value, Inputs, Level 1 [Member] Investing activities Net Cash Provided by (Used in) Investing Activities [Abstract] Fair Value by Liability Class [Domain] Fair Value by Liability Class [Domain] Entity Small Business Entity Small Business Purchase price (in dollars per share) Share Based Compensation Arrangement by Share Based Payment Award, Purchased Price of Share Represents the purchase price per share of shares issued to employees under the plan. Undiscounted cash payment obligations Lessee, Operating Lease, Liability, Payment, Due [Abstract] AmerisourceBergen Drug Corporation AmerisourceBergen Drug Corporation [Member] AmerisourceBergen Drug Corporation 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 Beginning balance Ending balance Contract with Customer, Liability, Current Proceeds from maturities and redemptions of investments Proceeds from Sale and Maturity of Debt Securities, Available-for-sale Options exercised (in dollars per share) Share-based Compensation Arrangements by Share-based Payment Award, Options, Exercises in Period, Weighted Average Exercise Price Liabilities and stockholders’ equity Liabilities and Equity [Abstract] Derivative liability for exit fees Exit Fee derivative liability Derivative Financial Instruments, Liabilities [Member] Accounts payable Increase (Decrease) in Accounts Payable 2022 Exit Fee addition at fair value Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Purchases Derivative [Line Items] Derivative [Line Items] Gross To Net Sales Accrual And Reserve Classification [Domain] Gross To Net Sales Accrual And Reserve Classification [Domain] Gross To Net Sales Accrual And Reserve Classification [Domain] Net Loss Per Share Earnings Per Share [Text Block] Operating expenses: Operating Expenses [Abstract] Entity Interactive Data Current Entity Interactive Data Current Short-term investments: Debt Securities, Available-for-Sale, Fair Value to Amortized Cost, after Allowance for Credit Loss [Abstract] Cash and Cash Equivalents [Domain] Cash and Cash Equivalents [Domain] Issuance of common stock upon exercise of options Stock Issued During Period, Value, Stock Options Exercised Minimum Minimum [Member] 2022 Term Loan Term Loan 2022 [Member] Term Loan 2022 2024 Lessee, Operating Lease, Liability, to be Paid, Year Two Liabilities, fair value Financial and Nonfinancial Liabilities, Fair Value Disclosure Selling, general and administrative Selling, General and Administrative Expense Preferred stock, shares authorized Preferred Stock, Shares Authorized Entity Common Stock, Shares Outstanding Entity Common Stock, Shares Outstanding Short-term investments, Gross Unrealized Gains Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax Entity Address, State or Province Entity Address, State or Province Current liabilities: Liabilities, Current [Abstract] U.S. government-sponsored agency bonds US Government Corporations and Agencies Securities [Member] Receivable [Domain] Receivable [Domain] Issuance of common stock in at the market offering Stock Issued During Period, Value, New Issues Operating lease liabilities Increase (Decrease) in Operating Lease Liability Borrowing Debt Disclosure [Text Block] Beginning balance (shares) Ending balance (shares) Shares, Outstanding Options exercisable (in dollars per share) Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Exercise Price Equity Incentive Plans Share-based Payment Arrangement [Text Block] Level 3 Fair Value, Inputs, Level 3 [Member] Inventory Inventory Disclosure [Text Block] Derivative Instrument [Axis] Derivative Instrument [Axis] Issuance of common stock in at the market offering (shares) Stock Issued During Period, Shares, New Issues Term of agreement Term Of Agreement Term of agreement. Total operating lease liabilities Operating Lease, Liability Document Transition Report Document Transition Report Common stock, $0.0001 par value; 300,000,000 shares authorized; 136,330,360 and 130,182,535 shares issued and outstanding as of March 31, 2022 and December 31, 2021, respectively. Common Stock, Value, Issued Disaggregation of Revenue [Line Items] Disaggregation of Revenue [Line Items] Other income (expense), net Nonoperating Income (Expense) Inventory Inventory, Net [Abstract] Average Remaining Vesting Period (Years) Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Period for Recognition Outstanding balance, beginning (in dollars per share) Outstanding balance, ending (in dollars per share) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value Customer Customer Concentration Risk [Member] Basis of Presentation Basis of Accounting, Policy [Policy Text Block] Commitments and contingencies Commitments and Contingencies Total repayment obligations Long-term Debt, Fiscal Year Maturity [Abstract] Subsequent Event [Table] Subsequent Event [Table] Leases Lessee, Operating Leases [Text Block] Accumulated other comprehensive loss Accumulated Other Comprehensive Income (Loss), Net of Tax Entity Emerging Growth Company Entity Emerging Growth Company Prepayment premium (as a percent) Debt Instrument, Prepayment Fee, Percentage The percentage of fee payable on prepayment of debt. Proceeds from loan payable, net of issuance costs Proceeds from Debt, Net of Issuance Costs Remainder of 2022 Lessee, Operating Lease, Liability, to be Paid, Remainder of Fiscal Year Short-term available-for-sale securities contractual maturities, maximum Available-For-Sale Securities, Debt Securities, Current, Contractual Maturities, Maximum Available-For-Sale Securities, Debt Securities, Current, Contractual Maturities, Maximum 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. Cash and cash equivalents: Cash and Cash Equivalents, at Carrying Value [Abstract] 2020 Open Market Sales Agreement Open Market Sales Agreement 2020, At The Market Offering [Member] Open Market Sales Agreement 2020, At The Market Offering Cover [Abstract] Cover [Abstract] Total operating expenses Costs and Expenses Class of Stock [Axis] Class of Stock [Axis] Collaborative Arrangement and Arrangement Other than Collaborative [Axis] Collaborative Arrangement and Arrangement Other than Collaborative [Axis] Imputed interest expenses Lessee, Operating Lease, Liability, Undiscounted Excess Amount Exit fee, term (in years) Loan Agreement, Exit Fee, Term Loan Agreement, Exit Fee, Term 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] Prepaid expenses and other current assets Prepaid Expense and Other Assets, Current Comprehensive loss: Comprehensive Income (Loss), Net of Tax, Attributable to Parent [Abstract] Cash and cash equivalents, Amortized Cost Cash And Cash Equivalents, Amortized Cost Cash And Cash Equivalents, Amortized Cost Financial Instrument [Axis] Financial Instrument [Axis] Selling, general and administrative Selling, General and Administrative Expenses [Member] Total revenues Revenue Revenue from Contract with Customer, Excluding Assessed Tax Fosun Pharma Shanghai Fosun Pharmaceutical Industrial Development [Member] Represents Shanghai Fosun Pharmaceutical Industrial Development. Debt refinancing costs Gains (Losses) on Restructuring of Debt Knight Agreement License Agreement Development Commercialization Distribution In Canada [Member] Agreement for the development, commercialization and distribution fo tenapanor in Canada. The Knight Agreement. Stock options Share-based Payment Arrangement, Option [Member] Fair Value Hierarchy and NAV [Axis] Fair Value Hierarchy and NAV [Axis] Document Quarterly Report Document Quarterly Report Common Stock Common Stock [Member] Variable Rate [Axis] Variable Rate [Axis] Loss from operations Operating Income (Loss) Debt Securities, Available-for-sale [Line Items] Debt Securities, Available-for-sale [Line Items] Current portion of operating lease liability Current portion of lease liabilities Less: Current portion of operating lease liability Operating Lease, Liability, Current Short-term investments, Gross Unrealized Losses Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax Organization and Basis of Presentation Organization, Consolidation, Basis of Presentation, Business Description and Accounting Policies [Text Block] Collaboration and Licensing Agreements Collaborative Arrangement Disclosure [Text Block] ESPP Employee Stock Purchase Plan [Member] Employee Stock Purchase Plan [Member] Document Fiscal Year Focus Document Fiscal Year Focus Stock-based compensation Share-based Payment Arrangement, Noncash Expense Variable Rate [Domain] Variable Rate [Domain] Additional Paid-In Capital Additional Paid-in Capital [Member] Cash and cash equivalents Cash and cash equivalents, Fair Value Cash and Cash Equivalents, at Carrying Value Depreciation expense Depreciation Weighted-average sales price per share Sale Of Stock, Weighted-Average Price Per Share Sale Of Stock, Weighted-Average Price Per Share Long-term Debt, Type [Domain] Long-term Debt, Type [Domain] Cash and Cash Equivalents [Abstract] Cash and Cash Equivalents [Abstract] Gross product revenue Revenue, Product and Service Benchmark [Member] Aggregate cost of revenue recognized Cost Of Revenue, Aggregate Amount Recognized Cost of revenue, aggregate amount recognized. Activity related to 2022 sales Contract With Customer, Gross To Net Sales, Accrual Activity During Current Period Contract With Customer, Gross To Net Sales, Accrual Activity During Current Period AZ Termination Agreement AstraZeneca Termination Agreement [Member] AstraZeneca Termination Agreement Accrued and other liabilities Increase (Decrease) in Accrued Liabilities Arrangements and Non-arrangement Transactions [Domain] Collaborative Arrangement and Arrangement Other than Collaborative [Domain] Purchases of property and equipment Payments to Acquire Property, Plant, and Equipment Maximum Maximum [Member] Share-based Payment Arrangement [Abstract] Share-based Payment Arrangement [Abstract] Total liabilities Liabilities Award Type [Axis] Award Type [Axis] Options granted (in dollars per share) Share-based Compensation Arrangements by Share-based Payment Award, Options, Grants in Period, Weighted Average Exercise Price Financing activities Net Cash Provided by (Used in) Financing Activities [Abstract] Percentage of non-royalty revenue Percentage Of Non-Royalty Revenue Represents percentage of non-royalty revenue. Summary of Undiscounted Cash Payment Obligations for Operating Lease Liabilities Lessee, Operating Lease, Liability, Maturity [Table Text Block] Total stockholders’ equity Beginning balance Ending balance Stockholders' Equity Attributable to Parent Issuance of common stock for services (shares) Stock Issued During Period, Shares, Issued for Services Common stock, shares issued Common Stock, Shares, Issued Preferred stock, shares issued Preferred Stock, Shares Issued City Area Code City Area Code Entity Address, City or Town Entity Address, City or Town Product supply revenue Product Supply Revenue [Member] Product Supply Revenue Exit fee (percent) Exit Fee, Percentage Exit Fee, Percentage Stockholders’ equity: Stockholders' Equity Attributable to Parent [Abstract] Commission on sale of stock per agreement (percent) Stock Issuance Cost, Commission, Percent Stock Issuance Cost, Commission, Percent Operating lease liability, net of current portion Operating lease liability, net of current portion Operating Lease, Liability, Noncurrent Measurement Frequency [Domain] Measurement Frequency [Domain] Term loan face amount Debt Instrument, Face Amount Interest expense Interest Expense Accrued compensation and benefits Increase (Decrease) in Employee Related Liabilities Collaborative development revenue Collaborative Development [Member] Collaborative Development [Member] Accumulated deficit Retained Earnings (Accumulated Deficit) RSUs Restricted Stock Units (RSUs) [Member] Statement of Stockholders' Equity [Abstract] Statement of Stockholders' Equity [Abstract] 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 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 Entity Filer Category Entity Filer Category AstraZeneca Astrazeneca [Member] Represents information pertaining to AstraZeneca. Term of payment of license fee, first installment Term Of Payment Of License Fee, First Installment Term of payment of first installment fee. Other-than-temporary impairment Other-than-temporary Impairment Loss, Debt Securities, Available-for-sale 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 Income Statement [Abstract] Income Statement [Abstract] Number of payment tranches for fee receivable for reduction in royalty rate Collaborative Arrangement, Fee Receivable For Reduction In Royalty Rate, Number Of Payment Tranches Collaborative Arrangement, Fee Receivable For Reduction In Royalty Rate, Number Of Payment Tranches Entity Registrant Name Entity Registrant Name Number of separate collaborative agreements Number Of Separate Collaborative Agreements Number of separate collaborative agreements. Inventory Disclosure [Abstract] Asset Class [Domain] Asset Class [Domain] Schedule of Changes in Fair Value of Derivative Liability Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Table Text Block] Cash and cash equivalents, Gross Unrealized Gains Cash And Cash Equivalents, Gross Unrealized Gains Cash And Cash Equivalents, Gross Unrealized Gains Second installment of upfront license fees Collaboration And Licensing Agreements, Upfront License Fees, Second Installment Collaboration And Licensing Agreements, Upfront License Fees, Second Installment Options forfeited (in dollars per share) Share-based Compensation Arrangements by Share-based Payment Award, Options, Forfeitures in Period, Weighted Average Exercise Price Provision for income taxes Income Tax Expense (Benefit) 2018 Term Loan Term Loan 2018 [Member] Term Loan 2018 Accounts receivable Accounts Receivable, after Allowance for Credit Loss, Current Amendment Flag Amendment Flag Equity Components [Axis] Equity Components [Axis] Schedule of Securities Classified as Cash, Cash Equivalents and Investments Cash, Cash Equivalents and Investments [Table Text Block] Entity Tax Identification Number Entity Tax Identification Number Fair Value Disclosures [Abstract] Fair Value Disclosures [Abstract] Document Fiscal Period Focus Document Fiscal Period Focus Total current assets Assets, Current Sale of Stock [Domain] Sale of Stock [Domain] Total undiscounted operating lease payments Lessee, Operating Lease, Liability, to be Paid Concentration Risk Type [Domain] Concentration Risk Type [Domain] Disaggregation of Revenue [Table] Disaggregation of Revenue [Table] Denominator: Weighted Average Number of Shares Outstanding Reconciliation [Abstract] Forfeited (shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period Fosun Agreement License Agreement Development Commercialization Distribution In China [Member] Agreement for the development, commercialization and distribution of tenapanor in China. The Fosun Agreement. Issuance of derivative in connection with issuance of loan payable Derivative Issued Derivative Issued Inventory Total Inventory, Net Deferred revenue - non-current Change In Contract With Customer Liability, Noncurrent, Rollforward [Roll Forward] Change In Contract With Customer Liability, Noncurrent, Rollforward Schedule of Chargebacks, Discounts and Reserve Balances Schedule Of Gross To Net Sales Accruals [Table Text Block] Schedule Of Gross To Net Sales Accruals 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] Statement of Financial Position [Abstract] Statement of Financial Position [Abstract] Term Loan A Term Loan 2022 A [Member] Term Loan 2022 A Exit fee, net product revenue threshold Loan Agreement, Exit Fee, Net Product Revenue Threshold Metric, Trailing Six Month Basis, Minimum Loan Agreement, Exit Fee, Net Product Revenue Threshold Metric, Trailing Six Month Basis, Minimum Increase due to unbilled prepayments recorded during the period Contract With Customer, Liability, Increase Due To Unbilled Prepayments Recorded Contract With Customer, Liability, Increase Due To Unbilled Prepayments Recorded Fair Value Measurements Fair Value Measurement, Policy [Policy Text Block] Current portion of long-term debt Less: Current portion of long-term debt Long-term Debt, Current Maturities 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. Product and Service [Axis] Product and Service [Axis] Preferred stock, par value (in dollars per share) Preferred Stock, Par or Stated Value Per Share Amortization of deferred compensation for services Amortization of Deferred Charges Equity Component [Domain] Equity Component [Domain] Aggregate amount paid Payments Of Uncharged License Fees, Aggregate Amount Paid Payments of uncharged license fees, aggregate amount paid. After second anniversary to maturity date Debt Instrument, Redemption, Period Three [Member] 2023 Lessee, Operating Lease, Liability, to be Paid, Year One 2021 Open Market Sales Agreement Open Market Sales Agreement 2021, At The Market Offering [Member] Open Market Sales Agreement 2021, At The Market Offering Non-cash interest associated with debt discount accretion Amortization of Debt Discount (Premium) Statement [Line Items] Statement [Line Items] Gain on sale of equipment Gain (Loss) on Disposition of Property Plant Equipment, Excluding Oil and Gas Property and Timber Property Right-of-use assets and lease liabilities Assets and Liabilities, Lessee [Abstract] Weighted-Average Exercise Price per Share Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Abstract] 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 Short-term investments, Fair Value Debt Securities, Available-for-sale 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. Counterparty Name [Domain] Counterparty Name [Domain] 2026 Lessee, Operating Lease, Liability, to be Paid, Year Four Debt Disclosure [Abstract] Debt Disclosure [Abstract] Potential development milestones Collaborative Arrangement, Potential Development Milestones Collaborative Arrangement, Potential Development Milestones Loss before provision for income taxes Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest Level 2 Fair Value, Inputs, Level 2 [Member] Cash, Cash Equivalents and Investments Cash, Cash Equivalents, and Short-term Investments [Text Block] Subsidiary, Sale of Stock [Line Items] Subsidiary, Sale of Stock [Line Items] Deferred revenue, non-current Beginning balance Ending balance Contract with Customer, Liability, Noncurrent Short-term investments, Amortized Cost Debt Securities, Available-for-sale, Amortized Cost Customer [Axis] Customer [Axis] Purchases of investments Payments to Acquire Short-term Investments Use of Estimates Use of Estimates, Policy [Policy Text Block] Schedule of Computation of Net Loss Per Common Share Schedule of Earnings Per Share, Basic and Diluted [Table Text Block] Options granted (shares) Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross Asset Class [Axis] Asset Class [Axis] Summary of Stock-Based Compensation Expense Recognized Share-based Payment Arrangement, Expensed and Capitalized, Amount [Table Text Block] Title of 12(b) Security Title of 12(b) Security Proceeds from issuance of common stock in at the market offering, net of issuance costs Proceeds from Issuance of Common Stock Total assets Assets Board of directors Director [Member] Plan Name [Domain] Plan Name [Domain] Common stock, shares authorized Common Stock, Shares Authorized Cash paid for interest Interest Paid, Excluding Capitalized Interest, Operating Activities Numerator: Net Income (Loss) Attributable to Parent [Abstract] Repayment of 2018 Loan, net of settlement costs Repayments of Secured Debt Title of Individual [Axis] Title of Individual [Axis] Document Type Document Type Schedule of Restricted Stock Units Activity Schedule of Nonvested Restricted Stock Units Activity [Table Text Block] Research and development Research and Development Expense Products and Services [Domain] Product and Service [Domain] Derivative Contract [Domain] Derivative Contract [Domain] Share-based Compensation Arrangement by Share-based Payment Award [Line Items] Share-based Compensation Arrangement by Share-based Payment Award [Line Items] Summary of Total Unrecognized Stock-Based Compensation Expense, Net of Estimated Forfeitures Share-based Payment Arrangement, Nonvested Award, Cost [Table Text Block] Cash Cash [Member] Measurement Frequency [Axis] Measurement Frequency [Axis] Net cash used in operating activities Net Cash Provided by (Used in) Operating Activities Agreed amount for exit fee upon occurrence of certain conditions Agreed amount for exit fee upon change of control or regulatory approval Derivative Liability, Notional Amount Fair Value, Recurring and Nonrecurring [Table] Fair Value, Recurring and Nonrecurring [Table] Summary of Lease Costs Lease, Cost [Table Text Block] Schedule of Long-term Debt Instruments [Table] Schedule of Long-term Debt Instruments [Table] Subsequent Event [Line Items] Subsequent Event [Line Items] Commercial paper Commercial Paper, Not Included with Cash and Cash Equivalents [Member] Accrued expenses and other current liabilities Accrued Liabilities and Other Liabilities Less: Unaccreted value of final fee Debt Instrument, Fee Amount Shares used in computing net loss per share - basic Weighted average common shares outstanding - basic Weighted Average Number of Shares Outstanding, Basic Net loss per common share - diluted (in dollars per share) Earnings Per Share, Diluted Non-cash lease expense Operating Lease, Right-of-Use Asset, Amortization Expense Knight Knight Therapeutics Inc [Member] Represents information pertaining to Knight Therapeutics Inc. Product sales, net Product [Member] Cash paid for income taxes Income Taxes Paid, Net Subsequent Events Subsequent Events [Text Block] Lease costs Lease, Cost [Abstract] Comprehensive loss Comprehensive Income (Loss), Net of Tax, Attributable to Parent Cash and cash equivalents, Gross Unrealized Losses Cash And Cash Equivalents, Gross Unrealized Losses Cash And Cash Equivalents, Gross Unrealized Losses Cost of revenue Cost of Revenue Net cash provided by (used in) financing activities Net Cash Provided by (Used in) Financing Activities Term Loan Loans Payable [Member] Collaboration and Licensing Agreements Collaboration and Licensing Agreements n/a Corporate bonds Corporate Debt Securities [Member] Fair Value Measurements Fair Value Disclosures [Text Block] Accounts payable Accounts Payable, Current Concentration Risk Type [Axis] Concentration Risk Type [Axis] 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] Accumulated Other Comprehensive Income AOCI Attributable to Parent [Member] Inventory Increase (Decrease) in Inventories Deferred revenue - current Change In Contract With Customer Liability, Current, Rollforward [Roll Forward] Change In Contract With Customer Liability, Current, Rollforward Common stock, shares outstanding Common Stock, Shares, Outstanding Financial Instruments [Domain] Financial Instruments [Domain] Derivative [Table] Derivative [Table] Revenues: Revenues [Abstract] Document Period End Date Document Period End Date Issuance of common stock upon vesting of restricted stock units (shares) Stock Issued During Period, Shares, Restricted Stock Award, Net of Forfeitures Collaborators Accounts Receivable, Collaborator [Member] Accounts Receivable, Collaborator Entity Central Index Key Entity Central Index Key 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 Concentration Risk Benchmark [Domain] Concentration Risk Benchmark [Domain] Discounts and Chargebacks Contract With Customer, Discounts And Chargebacks [Member] Contract With Customer, Discounts And Chargebacks Number of Shares Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward] Income Statement Location [Domain] Income Statement Location [Domain] Debt Securities, Available-for-sale [Table] Debt Securities, Available-for-sale [Table] Supplementary disclosure of non-cash activities: Cash Flow, Noncash Investing and Financing Activities Disclosure [Abstract] Upfront license fees Collaboration And Licensing Agreements, Upfront License Fees Collaboration And Licensing Agreements, Upfront License Fees Maximum potential payment per agreement Collaborative Arrangement, Potential Payment Per Termination Agreement, Maximum Collaborative Arrangement, Potential Payment Per Termination Agreement, Maximum Property and equipment, net Property, Plant and Equipment, Net Rebates Contract With Customer, Rebates [Member] Contract With Customer, Rebates Cash and investments Total cash equivalents and investments, Fair Value Investments and Cash Share-based Payment Arrangement, Expensed and Capitalized, Amount [Table] Share-based Payment Arrangement, Expensed and Capitalized, Amount [Table] Debt Instrument [Line Items] Debt Instrument [Line Items] Trading Symbol Trading Symbol Earnings Per Share [Abstract] Earnings Per Share [Abstract] Future obligation upon loan funding or other events Loan Agreement, Future Obligation Upon Funding Or Other Events Loan Agreement, Future Obligation Upon Funding Or Other Events Finished goods Inventory, Finished Goods, Gross Contingent liabilities Loss Contingency Accrual Options outstanding balance, beginning (in dollars per share) Options outstanding balance, ending (in dollars per share) Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price Long-term debt, net of current portion Long-term Debt, Excluding Current Maturities Liabilities, Fair Value Disclosure [Abstract] Liabilities, Fair Value Disclosure [Abstract] Stock-based compensation expense Share-based Payment Arrangement, Expense Cost of Revenue Cost of Goods and Service [Policy Text Block] Entity Current Reporting Status Entity Current Reporting Status Weighted-Average Grant Date Fair Value Per Share Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract] Total cash equivalents and investments, Gross Unrealized Gains Cash Cash Equivalents And Investments Gross Unrealized Gains Cash, cash equivalents and investments gross unrealized gains. Loan agreement covenant, cash and cash equivalents as percentage of outstanding loan balance, minimum Loan Agreement, Covenant, Cash And Cash Equivalents As Percentage Of Outstanding Loan Balance, Minimum Loan Agreement, Covenant, Cash And Cash Equivalents As Percentage Of Outstanding Loan Balance, Minimum Amortization of (discount) premium on investment securities Accretion (Amortization) of Discounts and Premiums, Investments Amortization of deferred financing costs Amortization of Debt Issuance Costs Counterparty Name [Axis] Counterparty Name [Axis] Common stock Common Class A [Member] 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 Term Loan B Term Loan 2022 B [Member] Term Loan 2022 B Common stock, par value (in dollars per share) Common Stock, Par or Stated Value Per Share Current assets: Assets, Current [Abstract] Payment terms Revenue, General Payment Terms Revenue, General Payment Terms Prior to first anniversary of closing date Debt Instrument, Redemption, Period One [Member] Leases [Abstract] Leases [Abstract] LIBOR London Interbank Offered Rate (LIBOR) [Member] Entity Address, Postal Zip Code Entity Address, Postal Zip Code Product Sales, Net and Reserves for Variable Consideration Revenue from Contract with Customer [Policy Text Block] Issuance of common stock upon exercise of options (shares) Options exercised (shares) Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period Shares used in computing net loss per share - diluted Weighted average common shares outstanding - diluted Weighted Average Number of Shares Outstanding, Diluted Recurring Fair Value, Recurring [Member] Total cash equivalents and investments, Cost Investments And Cash, Amortized Cost Investments And Cash, Amortized Cost Change in derivative liabilities Increase (Decrease) in Derivative Liabilities Long-term Debt, Type [Axis] Long-term Debt, Type [Axis] Schedule of Stock Option Activity Share-based Payment Arrangement, Option, Activity [Table Text Block] Floating per annum rate (percent) Debt Instrument, Basis Spread on Variable Rate McKesson Corporation McKesson Corporation [Member] McKesson Corporation Stockholders' Equity Stockholders' Equity Note Disclosure [Text Block] Statement of Cash Flows [Abstract] Statement of Cash Flows [Abstract] Entity Address, Address Line One Entity Address, Address Line One Net cash provided by investing activities Net Cash Provided by (Used in) Investing Activities Entity Address, Address Line Two Entity Address, Address Line Two Changes in operating assets and liabilities: Increase (Decrease) in Operating Capital [Abstract] Issuance of common stock under employee stock purchase plan Stock Issued During Period, Value, Employee Stock Purchase Plan Unrealized losses on available-for-sale securities Unrealized losses on available-for-sale securities Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, Net of Tax, Portion Attributable to Parent Net Cash Provided by (Used in) Operating Activities [Abstract] Net Cash Provided by (Used in) Operating Activities [Abstract] Vested (in dollars per share) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Weighted Average Grant Date Fair Value Entity Shell Company Entity Shell Company Gross-to-net sales accruals and reserves Contract With Customer, Gross To Net Sales Accrual [Roll Forward] Contract With Customer, Gross To Net Sales Accrual Total current liabilities Liabilities, Current Class of Stock [Domain] Class of Stock [Domain] Additional details Lessee, Operating Lease, Description [Abstract] Money market funds Money Market Funds [Member] Current Fiscal Year End Date Current Fiscal Year End Date Less: Unamortized discount Debt Instrument, Unamortized Discount (Premium) and Debt Issuance Costs, Net Debt Instrument, Name [Domain] Debt Instrument, Name [Domain] Proceeds from ESPP Proceeds from Stock Plans Statement [Table] Statement [Table] 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. Collaborative Arrangement and Arrangement Other than Collaborative [Table] Collaborative Arrangement and Arrangement Other than Collaborative [Table] Asset-backed securities Asset-backed Securities [Member] Recent Accounting Pronouncements New Accounting Pronouncements, Policy [Policy Text Block] 2018 Exit Fee Exit Fee 2018 [Member] Exit Fee 2018 Investment in continuous unrealized loss position for more than one year Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Number of Positions Unrecognized Compensation Expense Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Amount Debt Instrument, Redemption, Period [Domain] Debt Instrument, Redemption, Period [Domain] Statistical Measurement [Axis] Statistical Measurement [Axis] Accounts Receivable Accounts Receivable [Policy Text Block] Subsequent event Subsequent Event [Member] Stockholders' Equity Note [Abstract] Stockholders' Equity Note [Abstract] 2022 Exit Fee Exit Fee 2022 [Member] Exit Fee 2022 Licensing revenue License [Member] Inventory Inventory, Policy [Policy Text Block] 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] Addition to floating per annum rate (percent) Debt Instrument, Variable Rate, Base Option Debt Instrument, Variable Rate, Base Option Subsequent Event Type [Axis] Subsequent Event Type [Axis] Operating lease expense Operating Lease, Cost Cash and Cash Equivalents [Axis] Cash and Cash Equivalents [Axis] Debt Instrument, Redemption, Period [Axis] Debt Instrument, Redemption, Period [Axis] Concentration Risk Benchmark [Axis] Concentration Risk Benchmark [Axis] 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 Collaborative Arrangement and Arrangement Other than Collaborative [Line Items] Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]