Entity Central Index Key Inventory gross before other inventory. Deferred tax assets other non-current liabilities. 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 Filer Category Entity Filer Category Entity Small Business Entity Small Business Entity Emerging Growth Company Entity Emerging Growth Company Entity Ex Transition Period Entity Ex Transition Period Entity Shell Company Entity Shell Company Entity Common Stock, Shares Outstanding Entity Common Stock Shares Outstanding 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 Public Float Entity Public Float Statement Of Financial Position [Abstract] Assets Assets [Abstract] Current assets: Assets Current [Abstract] Cash and cash equivalents Cash And Cash Equivalents At Carrying Value Available for sale securities Available For Sale Securities Debt Securities Inventory Inventory Net Accounts receivable Accounts Receivable Net 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 Goodwill Goodwill Other intangible assets, net Other Intangible Assets Net Other assets 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 expenses Accrued Liabilities Current Debt Lines Of Credit Current Short-term deferred revenue Contract With Customer Liability Current Total current liabilities Liabilities Current Deferred rent, net of current portion Deferred Rent Credit Noncurrent Deferred revenue, net of current portion Contract With Customer Liability Noncurrent Deferred tax liabilities Deferred Tax Liabilities Other non-current liabilities Other Liabilities Noncurrent Total liabilities Liabilities Commitments and contingencies (Note 10) Commitments And Contingencies Stockholders' equity: Stockholders Equity [Abstract] Preferred stock $0.00001 par value, 25,000,000 shares authorized at December 31, 2018 and 2017; 0 shares issued and outstanding at December 31, 2018 and 2017 Preferred Stock Value Common stock: $0.00001 par value; 175,000,000 shares authorized at December 31, 2018 and 2017; 116,887,518 and 47,612,619 shares issued and outstanding at December 31, 2018 and 2017, respectively Common Stock Value Additional paid-in capital Additional Paid In Capital Common Stock Accumulated other comprehensive loss Accumulated Other Comprehensive Income Loss Net Of Tax Accumulated deficit Retained Earnings Accumulated Deficit Total stockholders' equity Stockholders Equity 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 Amortization of intangible assets product. License expense. Income Statement [Abstract] Statement [Table] Statement [Table] Product and Service Product Or Service [Axis] Product and Service Products And Services [Domain] Product Revenue, Net Product [Member] License, collaboration and other revenue. License, Collaboration and Other Revenue License Collaboration And Other Revenue [Member] Statement [Line Items] Statement [Line Items] Revenues: Revenues [Abstract] Total revenues Revenue From Contract With Customer Excluding Assessed Tax Cost of goods sold: Cost Of Revenue [Abstract] Product Cost Of Goods And Services Sold Type of Cost, Good or Service [Extensible List] Type Of Cost Good Or Service Extensible List Amortization of intangibles Amortization Of Intangible Assets Product Total cost of goods sold Cost Of Revenue Operating expenses: Operating Expenses [Abstract] Research and development Research And Development Expense Selling, general and administrative Selling General And Administrative Expense License expense License Expense Total operating expenses Operating Expenses Operating loss Operating Income Loss Other income (expense): Nonoperating Income Expense [Abstract] Interest income Interest Income Expense Nonoperating Net Other income/(expense) Other Nonoperating Income Expense Net loss before income taxes Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest Benefit for income taxes Income Tax Expense Benefit Net loss Net Income Loss Net loss per share - basic and diluted Earnings Per Share Basic And Diluted Weighted-average number of common shares - basic and diluted Weighted Average Number Of Share Outstanding Basic And Diluted Comprehensive loss: Comprehensive Income Net Of Tax [Abstract] Other comprehensive gain (loss) - unrealized gain (loss) on securities Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Net Of Tax Total comprehensive loss Comprehensive Income Net Of Tax Statement Of Stockholders Equity [Abstract] Equity Components Statement Equity Components [Axis] Equity Component Equity Component [Domain] Common Stock Common Stock [Member] Additional Paid-In Capital Additional Paid In Capital [Member] Treasury Stock Treasury Stock [Member] Unrealized Gain/Loss Accumulated Net Unrealized Investment Gain Loss [Member] Accumulated Deficit Retained Earnings [Member] Balance Balance, shares Keryx Merger Stock Issued During Period Value Acquisitions Keryx Merger, shares Stock Issued During Period Shares Acquisitions Issuance of Baupost Additional Shares Stock Issued During Period Value Conversion Of Convertible Securities Issuance of Baupost Additional Shares, shares Stock Issued During Period Shares Conversion Of Convertible Securities Issuance of common stock, net of issuance costs Stock Issued During Period Value New Issues Issuance of common stock, net of issuance costs, shares Stock Issued During Period Shares New Issues Proceeds from sale of stock under employee stock purchase plan Stock Issued During Period Value Employee Stock Purchase Plan Proceeds from sale of stock under employee stock purchase plan, shares Stock Issued During Period Shares Employee Stock Purchase Plans Forfeitures of restricted common stock Stock Issued During Period Value Restricted Stock Award Forfeitures Forfeitures of restricted common stock, shares Stock Issued During Period Shares Restricted Stock Award Forfeited Exercise of options Stock Issued During Period Value Stock Options Exercised Exercise of options, shares Stock Issued During Period Shares Stock Options Exercised Share-based compensation expense Adjustments To Additional Paid In Capital Sharebased Compensation Requisite Service Period Recognition Value Restricted stock unit vesting, shares Stock Issued During Period Shares Restricted Stock Award Net Of Forfeitures Issuance of common stock warrants Adjustments To Additional Paid In Capital Warrant Issued Unrealized gain/loss Other Comprehensive Income Loss Available For Sale Securities Adjustment Net Of Tax Treasury shares retired (8,643) Treasury Stock Retired Cost Method Amount Net loss Balance Balance, shares Treasury shares retired Treasury Stock Shares Retired Noncash interest expense. Fair value write-up of inventory sold. Increase (decrease) in deferred rent. Payments to acquire businesses net of acquired cash and restricted cash. Proceeds from issuance of common stock net of issuance costs. Deferred follow on offering issuance costs. Statement Of Cash Flows [Abstract] Operating activities: Net Cash Provided By Used In Operating Activities [Abstract] 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] Depreciation and amortization Depreciation Depletion And Amortization Amortization of intangibles Amortization Of Intangible Assets Amortization of premium/discount on investments Accretion Amortization Of Discounts And Premiums Investments Non-cash interest expense Noncash Interest Expense Non-cash merger expense Noncash Merger Related Costs Loss on disposal of property and equipment Gain Loss On Disposition Of Assets Fair value write-up of inventory sold Fair Value Write Up Of Inventory Sold Stock-based compensation Share Based Compensation Deferred income taxes Fair value of warrants issued for license Fair Value Adjustment Of Warrants Changes in operating assets and liabilities: Increase Decrease In Operating Capital [Abstract] Accounts receivable Increase Decrease In Accounts Receivable Inventory Increase Decrease In Inventories Prepaid expenses and other current assets Increase Decrease In Prepaid Deferred Expense And Other Assets Other long-term assets Increase Decrease In Other Noncurrent Assets Accounts payable Increase Decrease In Accounts Payable Accrued expense Increase Decrease In Accrued Liabilities Deferred revenue Increase Decrease In Contract With Customer Liability Deferred rent Increase Decrease In Deferred Rent Net cash provided by (used in) operating activities Net Cash Provided By Used In Operating Activities Investing activities: Net Cash Provided By Used In Investing Activities [Abstract] Acquisition of business, net of acquired cash and restricted cash Payments To Acquire Businesses Net Of Acquired Cash And Restricted Cash Purchase of equipment Payments To Acquire Property Plant And Equipment Proceeds from the maturities of available for sale securities Proceeds From Maturities Prepayments And Calls Of Available For Sale Securities Proceeds from sales of available for sale securities Proceeds From Sale Of Available For Sale Securities Debt Purchase of available for sale securities Payments To Acquire Available For Sale Securities Debt Net cash provided by (used in) investing activities Net Cash Provided By Used In Investing Activities Financing activities: Net Cash Provided By Used In Financing Activities [Abstract] Proceeds from the issuance of common stock, net of issuance costs Proceeds From Issuance Of Common Stock Net Of Issuance Costs Proceeds from the sale of stock under employee stock purchase plan Proceeds From Stock Plans Proceeds from the exercise of stock options Proceeds From Stock Options Exercised Payments on capital lease obligations Repayments Of Long Term Capital Lease Obligations Net cash provided by financing activities Net Cash Provided By Used In Financing Activities Increase (decrease) in cash, cash equivalents, and restricted cash Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Period Increase Decrease Including Exchange Rate Effect Cash, cash equivalents, and restricted cash at beginning of the period Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Cash, cash equivalents, and restricted cash at end of the period Non-cash financing activities Noncash Investing And Financing Items [Abstract] Fair value of shares and equity awards issued in acquisition Stock Issued1 Unpaid follow-on offering costs Deferred Follow On Offering Issuance Costs Accounting Policies [Abstract] Nature of Organization and Operations Nature Of Operations Summary of Significant Accounting Policies Significant Accounting Policies [Text Block] Revenue From Contract With Customer [Abstract] Product Revenue, Net Revenue From Contract With Customer [Text Block] Organization Consolidation And Presentation Of Financial Statements [Abstract] License, Collaboration and Other Significant Agreements Collaborative Arrangement Disclosure [Text Block] Business Combinations [Abstract] Business Combination Business Combination Disclosure [Text Block] Investments Debt And Equity Securities [Abstract] Available for Sale Securities Investments In Debt And Marketable Equity Securities And Certain Trading Assets Disclosure [Text Block] Fair Value Disclosures [Abstract] Fair Value of Financial Instruments Fair Value Disclosures [Text Block] Inventory Disclosure [Abstract] Inventory Inventory Disclosure [Text Block] Goodwill And Intangible Assets Disclosure [Abstract] Intangible Assets and Goodwill Goodwill And Intangible Assets Disclosure [Text Block] Payables And Accruals [Abstract] Accrued Expenses Accounts Payable And Accrued Liabilities Disclosure [Text Block] Debt Disclosure [Abstract] Debt Debt Disclosure [Text Block] Warrant disclosure. Warrant disclosure. Warrant Disclosure [Abstract] Warrant Warrant Disclosure [Text Block] Equity [Abstract] Stockholders' Equity Stockholders Equity Note Disclosure [Text Block] Income Tax Disclosure [Abstract] Income Taxes Income Tax Disclosure [Text Block] Compensation And Retirement Disclosure [Abstract] Employee Retirement Plan Pension And Other Postretirement Benefits Disclosure [Text Block] Commitments And Contingencies Disclosure [Abstract] Commitments and Contingencies Commitments And Contingencies Disclosure [Text Block] Earnings Per Share [Abstract] Net Loss per Share Earnings Per Share [Text Block]