Entity Central Index Key Document and entity information. Document And Entity Information [Abstract] Document Type Document Type Amendment Flag Amendment Flag Document Period End Date Document Period End Date Document Fiscal Year Focus Document Fiscal Year Focus Document Fiscal Period Focus Document Fiscal Period Focus Trading Symbol Trading Symbol Entity Registrant Name Entity Registrant Name Entity Central Index Key Current Fiscal Year End Date Current Fiscal Year End Date Entity Well-known Seasoned Issuer Entity Well Known Seasoned Issuer Entity Voluntary Filers Entity Voluntary Filers Entity Current Reporting Status Entity Current Reporting Status Entity Filer Category Entity Filer Category Entity Public Float Entity Public Float Entity Common Stock, Shares Outstanding Entity Common Stock Shares Outstanding Prepaid research and development current. Accrued research and development expense. Accrued liabilities and other liabilities current. Contractual obligation to collaborator, noncurrent. Statement Of Financial Position [Abstract] Assets Assets [Abstract] Current assets: Assets Current [Abstract] Cash and cash equivalents Cash And Cash Equivalents At Carrying Value Short-term investments Short Term Investments Restricted cash (SRX Cardio) Restricted Cash And Cash Equivalents At Carrying Value Receivables from collaborators Accounts Receivable Net Current Prepaid research and development Prepaid Research And Development Current Prepaid expenses and other current assets Prepaid Expense And Other Assets Current Total current assets Assets Current Property and equipment, net Property Plant And Equipment Net Intangible asset Intangible Assets Net Including Goodwill Long-term investments Long Term Investments Prepaid and other long-term assets Prepaid Expense And Other Assets Noncurrent Total assets Assets Liabilities and stockholders’ equity Liabilities And Stockholders Equity [Abstract] Current liabilities: Liabilities Current [Abstract] Accounts payable Accounts Payable Current Accrued compensation and employee benefits Employee Related Liabilities Current Accrued research and development Accrued Research And Development Expense Accrued and other liabilities Accrued Liabilities And Other Liabilities Current Deferred revenue, current portion Deferred Revenue Current Total current liabilities Liabilities Current Notes payable, long-term Long Term Notes Payable Long term obligation to Collaborator Contractual Obligation To Collaborator Noncurrent Deferred revenue, long-term Deferred Revenue Noncurrent Other long-term liabilities Other Liabilities Noncurrent Total liabilities Liabilities Stockholders’ equity: Stockholders Equity [Abstract] Preferred stock, $0.001 par value, 5,000,000 shares authorized; no shares issued and outstanding Preferred Stock Value Common stock, $0.001 par value, 100,000,000 shares authorized at December 31, 2016 and 2015; 56,544,218 shares and 56,359,515 shares issued and outstanding at December 31, 2016 and 2015, respectively Common Stock Value Additional paid-in capital Additional Paid In Capital Accumulated deficit Retained Earnings Accumulated Deficit Accumulated other comprehensive loss Accumulated Other Comprehensive Income Loss Net Of Tax Total Portola stockholders’ equity Stockholders Equity Noncontrolling interest (SRX Cardio) Minority Interest Total stockholders' equity Stockholders Equity Including Portion Attributable To Noncontrolling Interest Total liabilities and stockholders’ equity Liabilities And Stockholders Equity Preferred stock, par value Preferred Stock Par Or Stated Value Per Share Preferred stock, shares authorized Preferred Stock Shares Authorized Preferred stock, shares issued Preferred Stock Shares Issued Preferred stock, shares outstanding Preferred Stock Shares Outstanding Common stock, par value Common Stock Par Or Stated Value Per Share Common stock, shares authorized Common Stock Shares Authorized Common stock, shares issued Common Stock Shares Issued Common stock, shares outstanding Common Stock Shares Outstanding Income Statement [Abstract] Collaboration and license revenue License And Services Revenue Operating expenses: Operating Expenses [Abstract] Research and development Research And Development Expense Selling, general and administrative Selling General And Administrative Expense Total operating expenses Operating Expenses Loss from operations Operating Income Loss Interest and other income, net Nonoperating Income Expense Loss before taxes Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest Income tax benefit Income Tax Expense Benefit Net loss Profit Loss Net income attributable to noncontrolling interest (SRX Cardio) Net Income Loss Attributable To Noncontrolling Interest Net loss attributable to Portola Net Income Loss Net loss per share attributable to Portola common stockholders: Earnings Per Share [Abstract] Basic and diluted Earnings Per Share Basic And Diluted Shares used to compute net loss per share attributable to Portola common stockholders: Weighted Average Number Of Shares Outstanding [Abstract] Basic and diluted Weighted Average Number Of Share Outstanding Basic And Diluted Statement Of Income And Comprehensive Income [Abstract] Net loss Other comprehensive income: Other Comprehensive Income Loss Net Of Tax Period Increase Decrease [Abstract] Unrealized gain (loss) on available-for-sale securities, net of tax Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Net Of Tax Comprehensive loss Comprehensive Income Net Of Tax Including Portion Attributable To Noncontrolling Interest Comprehensive income attributable to noncontrolling interest (SRX Cardio) Comprehensive Income Net Of Tax Attributable To Noncontrolling Interest Total comprehensive loss attributable to Portola Comprehensive Income Net Of Tax Issuance of common stock shares upon cashless warrant exercises. Issuance of common stock from cashless warrant exercises. Stock issued during period shares restricted stock units and performance stock units net of forfeitures. Statement Of Stockholders Equity [Abstract] Statement [Table] Statement [Table] Noncontrolling Interest (SRX Cardio) Statement Equity Components [Axis] Equity Component Equity Component [Domain] Common Stock Common Stock [Member] Additional Paid-In Capital Additional Paid In Capital [Member] Accumulated Deficit Retained Earnings [Member] Accumulated Other Comprehensive Income (Loss) Accumulated Other Comprehensive Income [Member] Noncontrolling Interest (SRX Cardio) Noncontrolling Interest [Member] Sale of Stock Subsidiary Sale Of Stock [Axis] Sale of Stock Sale Of Stock Name Of Transaction [Domain] IPO I P O [Member] Statement [Line Items] Statement [Line Items] Balance at beginning of year Balance at beginning of year (in shares) Shares Outstanding Exercise of employee stock options for cash Stock Issued During Period Value Stock Options Exercised Exercise of employee stock options for cash (in shares) Stock Issued During Period Shares Stock Options Exercised Lapse of repurchase rights related to common shares issued pursuant to early exercises (in shares) Stock Issued During Period Shares Other Lapse of repurchase rights related to common shares issued pursuant to early exercises Stock Issued During Period Value Other Issuance of common stock upon cashless exercise of common stock warrants (shares) Issuance Of Common Stock Shares Upon Cashless Warrant Exercises Issuance of common stock upon cashless exercise of common stock warrants Issuance Of Common Stock From Cashless Warrant Exercises Issuance of common stock pursuant to ESPP purchase (in shares) Stock Issued During Period Shares Employee Stock Purchase Plans Issuance of common stock pursuant to ESPP purchase Stock Issued During Period Value Employee Stock Purchase Plan Issuance of common stock pursuant to RSU and PSU release (in shares) Stock Issued During Period Shares Restricted Stock Units And Performance Stock Units Net Of Forfeitures Issuance of stock (in shares) Stock Issued During Period Shares New Issues Issuance of stock Stock Issued During Period Value New Issues Employee stock-based compensation expense Adjustments To Additional Paid In Capital Sharebased Compensation Requisite Service Period Recognition Value Compensation expense relating to stock options granted to consultants Adjustments To Additional Paid In Capital Other Development Partner's noncontrolling interest upon consolidation Variable Interest Entity Initial Consolidation Gain Or Loss Net income attributable to Non Controlling interest (SRX Cardio) Dividends to Non Controlling interest (SRX Cardio)'s shareholders Minority Interest Decrease From Distributions To Noncontrolling Interest Holders Net loss Balance at end of the year Balance at end of the year (in shares) Balance at end of the year Non cash interest. Change in reserve for uncertain tax position. Increase decrease in prepaid research and development. Increase decrease in prepaid expense and other current assets. Increase decrease in accrued research and development. Proceeds from long term obligation to collaborator. Net change in accrued offering cost. Increase decrease in accounts payable related to purchases of property plant and equipment. Statement Of Cash Flows [Abstract] Operating activities Net Cash Provided By Used In Operating Activities Continuing Operations [Abstract] Net loss Adjustments to reconcile net loss to cash used in operating activities: Adjustments To Reconcile Net Income Loss To Cash Provided By Used In Operating Activities [Abstract] Depreciation and amortization Depreciation And Amortization Amortization of premium on investment securities Investment Income Amortization Of Premium Stock-based compensation expense Share Based Compensation Non-cash interest Non Cash Interest Change in reserve for uncertain tax position Change In Reserve For Uncertain Tax Position Unrealized loss on foreign currency forward contracts Unrealized Gain Loss On Derivatives Changes in operating assets and liabilities: Increase Decrease In Operating Capital [Abstract] Receivables from collaborations Increase Decrease In Accounts Receivable Prepaid research and development Increase Decrease In Prepaid Research And Development Prepaid expenses and other current assets Increase Decrease In Prepaid Expense And Other Current Assets Prepaid and other long-term assets Increase Decrease In Prepaid Deferred Expense And Other Assets Accounts payable Increase Decrease In Accounts Payable Accrued compensation and employee benefits Increase Decrease In Employee Related Liabilities Accrued research and development Increase Decrease In Accrued Research And Development Accrued and other liabilities Increase Decrease In Accrued Liabilities And Other Operating Liabilities Deferred revenue Increase Decrease In Deferred Revenue Other long-term liabilities Increase Decrease In Other Noncurrent Liabilities Net cash used in operating activities Net Cash Provided By Used In Operating Activities Continuing Operations Investing activities Net Cash Provided By Used In Investing Activities Continuing Operations [Abstract] Purchases of property and equipment Payments To Acquire Property Plant And Equipment (Increase)/decrease in restricted cash (SRX Cardio) Increase Decrease In Restricted Cash Purchases of investments Payments To Acquire Investments Proceeds from sales of investments Proceeds From Sale Of Available For Sale Securities Proceeds from maturities of investments Proceeds From Maturities Prepayments And Calls Of Available For Sale Securities Net cash provided by/ (used in) investing activities Net Cash Provided By Used In Investing Activities Continuing Operations Financing activities Net Cash Provided By Used In Financing Activities Continuing Operations [Abstract] Proceeds from public offering of common stock, net of underwriters discount Proceeds From Issuance Initial Public Offering Payment of public offering costs Payments Of Stock Issuance Costs Proceeds from issuance of common stock pursuant to equity award plans Proceeds From Issuance Of Shares Under Incentive And Share Based Compensation Plans Including Stock Options Dividends to Noncontrolling interest (SRX Cardio)'s shareholders Payments Of Dividends Minority Interest Proceeds from long-term note payables Proceeds From Repayments Of Notes Payable Proceeds from long-term obligation to Collaborator Proceeds From Long Term Obligation To Collaborator Net cash provided by financing activities Net Cash Provided By Used In Financing Activities Continuing Operations Net increase (decrease) in cash and cash equivalents Cash And Cash Equivalents Period Increase Decrease Cash and cash equivalents at beginning of year Cash and cash equivalents at end of year Noncash investing and financing activities: Noncash Investing And Financing Items [Abstract] Net change in accrued offering cost Net Change In Accrued Offering Cost Net change in accounts payable related to purchase of property and equipment Increase Decrease In Accounts Payable Related To Purchases Of Property Plant And Equipment Organization Consolidation And Presentation Of Financial Statements [Abstract] Organization Nature Of Operations Accounting Policies [Abstract] Summary of Significant Accounting Policies Basis Of Presentation And Significant Accounting Policies [Text Block] Fair Value Disclosures [Abstract] Fair Value Measurements Fair Value Disclosures [Text Block] Investments Debt And Equity Securities [Abstract] Financial Instruments Financial Instruments Disclosure [Text Block] Balance Sheet Related Disclosures [Abstract] Balance Sheet Components Supplemental Balance Sheet Disclosures [Text Block] Collaboration and License Agreements Collaborative Arrangement Disclosure [Text Block] Commitments And Contingencies Disclosure [Abstract] Purchase Commitments Commitments Disclosure [Text Block] Asset acquisition and license agreements. Research And Development [Abstract] Asset Acquisition and License Agreements Asset Acquisition Disclosure [Text Block] Debt Disclosure [Abstract] Notes Payable Debt Disclosure [Text Block] Commitments and Contingencies Commitments And Contingencies Disclosure [Text Block] Disclosure Of Compensation Related Costs Sharebased Payments [Abstract] Stock Based Compensation Disclosure Of Compensation Related Costs Share Based Payments [Text Block] Net Loss per Share Attributable to Portola Common Stockholders Earnings Per Share [Text Block] Compensation And Retirement Disclosure [Abstract] Employee Benefit Plan Pension And Other Postretirement Benefits Disclosure [Text Block] Income Tax Disclosure [Abstract] Income Taxes Income Tax Disclosure [Text Block] Related Party Transactions [Abstract] Related Party Transactions Related Party Transactions Disclosure [Text Block] Subsequent Events [Abstract] Subsequent Events Subsequent Events [Text Block] Quarterly Financial Information Disclosure [Abstract] Quarterly Financial Data (unaudited) Quarterly Financial Information [Text Block] Basis of Consolidation Consolidation Policy [Text Block] Use of Estimates Use Of Estimates Variable Interest Entities Consolidation Variable Interest Entity Policy In-process Research and Development Asset In Process Research And Development Policy Cash and Cash Equivalents Cash And Cash Equivalents Policy [Text Block] Investments in Marketable Securities Marketable Securities Policy Fair Value Measurements Fair Value Measurement Policy Policy [Text Block] Concentration of Risk Concentration Risk Credit Risk Property and Equipment Property Plant And Equipment Policy [Text Block] Impairment of Long-Lived Assets Impairment Or Disposal Of Long Lived Assets Policy [Text Block]