Accounts Payable and Accrued Liabilities Disclosure [Text Block] Accounts Payable and Accrued Expenses Accounts receivable - other Accumulated other comprehensive (loss) income Additional paid-in capital Capital expenditures Capital expenditures Statement of Financial Position [Abstract] Cash and cash equivalents Cash and cash equivalents at beginning of period Cash and cash equivalents at end of period Increase in accounts payable, accrued expenses, and other liabilities Increase (decrease) in accounts payable, accrued expenses, and other liabilities Increase in accounts receivable Increase in accounts receivable Decrease (increase) in prepaid expenses and other assets Decrease (increase) in prepaid expenses and other assets Changes in assets and liabilities Common Stock, authorized Common Stock, outstanding Common Stock Comprehensive Loss Cost of goods sold Expenses Current liabilities Liabilities, Current [Abstract] Total current liabilities Liabilities, Current Deferred revenue - other, current portion Deferred revenue - other Stock-based compensation expense Non-cash compensation expense Impairment charge on marketable securities Net realized loss (gain) on marketable securities Loss on early extinguishment of debt Loss on early extinguishment of debt Decrease (increase) in restricted cash Decrease (increase) in restricted cash Interest expense Interest expense LIABILITIES and STOCKHOLDERS' EQUITY Liabilities and Stockholders' Equity [Abstract] Total liabilities and stockholders' equity Liabilities and Stockholders' Equity Total liabilities Liabilities Marketable securities Marketable Securities Current Marketable securities Marketable Securities Noncurrent Cash flows from financing activities Net cash provided by (used in) financing activities Net Cash Provided by (Used in) Financing Activities Cash flows from investing activities Net cash (used in) provided by investing activities Net Cash Provided by (Used in) Investing Activities Cash flows from operating activities Net cash provided by (used in) operating activities Net Cash Provided by (Used in) Operating Activities Net loss Net loss Net decrease in cash and cash equivalents Cash and Cash Equivalents, Period Increase (Decrease) Future Impact of Recently Issued Accounting Standards Other income (expense) Total Other Income (Expense) Nonoperating Income (Expense) Investment income Loss from operations Operating Income (Loss) Revenues Revenues [Abstract] Total Revenues Revenues Change in net unrealized gain (loss) on marketable securities Preferred stock, authorized Preferred stock, issued Net proceeds from the issuance of Common Stock Sales or maturities of marketable securities Property, plant, and equipment, at cost, net of accumulated depreciation and amortization Purchases of marketable securities Purchases of marketable securities Accounts receivable from the sanofi-aventis Group Extinguishment of long-term debt Extinguishment of long-term debt Accumulated deficit Contract research and other Technology licensing Net product sales Subsequent Events Selling, general, and administrative Stockholders' equity Stockholders' Equity Attributable to Parent [Abstract] Assets, Current [Abstract] Current assets Assets, Current Total current assets Research and development Assets Total assets Other long term liabilities Statement [Table] ASSETS Assets [Abstract] Statement [Line Items] Class of Stock [Domain] Statement of Cash Flows Preferred stock, par value Common Stock, issued Increase (decrease) in deferred revenue Increase (decrease) in deferred revenue Other assets Preferred stock, outstanding Class of Stock [Axis] Common Stock, par value Total stockholders' equity Stockholders' Equity Attributable to Parent Beginning Balance Ending Balance Preferred stock, $.01 par value; 30,000,000 shares authorized; issued and outstanding-none Issuance of Common Stock in connection with Company 401(k) Savings Plan contribution Issuance of Common Stock in connection with exercise of stock options, net of shares tendered Conversion of Class A Stock to Common Stock Issuance of Common Stock in connection with Company 401(k) Savings Plan contribution (in shares) Issuance of Common Stock in connection with exercise of stock options, net of shares tendered (in shares) Conversion of Class A Stock to Common Stock (in shares) Total Expenses Costs and Expenses Beginning Balance (in shares) Ending Balance (in shares) Shares, Issued Net Loss Per Share Data Marketable Securities Marketable Securities [Text Block] Depreciation and amortization Total adjustments Adjustments to Reconcile Net Income (Loss) to Cash Provided by (Used in) Operating Activities Accounts payable and accrued expenses Lease - Tarrytown, New York Facilities Commitments and contingencies Adjustments to reconcile net loss to net cash provided by (used in) operating activities Prepaid expenses and other current assets Sum of the amounts paid in advance for capitalized costs that will be expensed with the passage of time or the occurrence of a triggering event, and will be charged against earnings within one year or the normal operating cycle, if longer, combined with the aggregate carrying amount, as of the balance sheet date, of current assets not separately presented elsewhere in the balance sheet. Current assets are expected to be realized or consumed within one year (or the normal operating cycle, if longer). Prepaid expenses and other current assets Deferred Revenue From Related Party Current Deferred revenue from sanofi-aventis, current portion The carrying amount of consideration received or receivable from related parties as of the balance sheet date on potential earnings that were not recognized as revenue in conformity with GAAP, and which are expected to be recognized as such within one year or the normal operating cycle, if longer, including sales, license fees, and royalties, but excluding interest income. The noncurrent portion of deferred revenue from related parties amount as of balance sheet date. Deferred revenue is a liability related to a revenue producing activity for which revenue has not yet been recognized, and is not expected to be recognized in the next twelve months. Generally, an entity records deferred revenue when it receives consideration from a customer before achieving certain criteria that must be met for revenue to be recognized in conformity with GAAP. Deferred Revenue From Related Party Noncurrent Deferred revenue from sanofi-aventis Facility Lease Obligation Noncurrent Represents the nocurrent portion of a liability recorded as a result of capitalizing the landlord's costs associated with a Build-to-Suit Lease on the Company's books. Facility lease obligations Net Loss Per Share Basic And Diluted The amount of net income or loss for the period per each share of common stock outstanding during the reporting period; and the amount of net income or loss for the period per each share of common stock and dilutive common stock equivalents outstanding during the reporting period. Net loss per share, basic and diluted Weighted Average Shares Outstanding Basic And Diluted Weighted average shares outstanding, basic and diluted Number of [basic] shares, after adjustment for contingently issuable shares and other shares not deemed outstanding, determined by relating the portion of time within a reporting period that common shares have been outstanding to the total time in that period; and the average number of shares issued and outstanding that are used in calculating diluted EPS, determined based on the timing of issuance of shares in the period. Proceeds From Facility Lease Obligation Proceeds in connection with facility lease obligation The cash inflow from proceeds received from lessor related to Build-to-Suit Lease. Notes to Financial Statements [Abstract] Document Type Amendment Flag Amendment Description Document Period End Date Entity Registrant Name Entity Central Index Key Current Fiscal Year End Date Entity Well-known Seasoned Issuer Entity Voluntary Filers Entity Current Reporting Status Entity Filer Category Entity Public Float Entity Common Stock, Shares Outstanding Statement, Equity Components [Axis] Equity Component [Domain] Class A [Member] Common Stock [Member] Additional Paid-in Capital [Member] Accumulated Deficit [Member] Accumulated Other Comprehensive Income (Loss) [Member] Comprehensive Loss [Member] Statement of Stockholders' Equity [Abstract] Net loss before income tax expense Income tax (benefit) expense Payments In Connection With Facility Lease Obligation Payments in connection with facility lease obligation The cash outflow for payments made to lessor related to Build-to-Suit Lease. Sanofi-aventis Collaboration Revenue Sanofi-aventis collaboration revenue Revenue earned during the period arising from products sold or services provided under the terms of a contract with a related party, not elsewhere specified in the taxonomy. Other Collaboration Revenue Other collaboration revenue Revenue earned during the period arising from products sold or services provided under the terms of a contract, not elsewhere specified in the taxonomy. Other Non-Cash Expense Other non-cash expenses Other expenses that are not cash transactions Facility Lease Obligations, Current Portion Facility lease obligations, current portion Represents the current portion of a liability recorded as a result of capitalizing the landlord's costs associated with a Build-to-Suit Lease on the Company's books. Change in net unrealized gain on marketable securities, net of tax effect Income Statement [Abstract] Statement of Cash Flows [Abstract] Entity [Text Block] Document Information [Text Block] Document Fiscal Year Focus Document Fiscal Period Focus Issuance of Restricted Common Stock under Long-Term Incentive Plan (in shares) Stock Issued During Period Shares Restricted Stock Award Gross Stock Issued During Period Value Restricted Stock Award Gross Issuance of Restricted Common Stock under Long-Term Incentive Plan ARCALYST (rilonacept) Product Revenue Disclosure of the revenue recognized, net product sales, cost of goods sold, and other information related to ARCALYST product line. Extension Of Technology Licensing Agreement With Astellas [Text Block] Disclosure of the amended and extended technology licensing agreement. Includes disclosure regarding payments to the Company, circumstances of termination, technology revenue, and other related information. Repurchases or repayment of notes payable Supplemental disclosure of cash flow information Cash paid for interest Cash paid for income taxes Organization and Business Summary of Significant Accounting Policies Collaboration and Contract Research Agreements Technology Licensing Agreement [Text Block] Technology Licensing Agreements Describe the terms of significant agreements to allow the utilization of Rights, generally of limited duration, under a license arrangement (for example, to sell or otherwise utilize specified products or processes in a specified territory). Property Plant and Equipment Deferred Revenue Convertible Debt Commitments And Contingencies Disclosure Text Block Commitments and Contingencies Stockholders Equity Income Taxes Unaudited Quarterly Results