Accrued Contract Research Costs Accrued contract research costs The carrying value as of the balance sheet date of obligations incurred and payable relating to service fees paid to contract manufacturers in connection with the production of clinical drug supplies and to contract research organizations in connection with preclinical studies and clinical trials. Used to reflect the current portion of liabilities (due within one year or within the normal operating cycle if longer). Accrued Liabilities Current Excluding Accrued Contract Research Costs Other accrued liabilities Carrying value as of the balance sheet date of obligations incurred and payable, pertaining to costs that are statutory in nature, are incurred on contractual obligations, or accumulate over time and for which invoices have not yet been received or will not be rendered. Examples include taxes, interest, rent and utilities. Excludes accrued contract research costs. (Used to reflect the current portion of the liabilities (due within one year or within the normal operating cycle if longer). Collaboration Revenues [Abstract] Collaboration revenues: License and Milestone Revenues License and milestone revenue Revenues earned by the entity under collaborative research and development agreements for nonrefundable, up-front license fees and milestone payments, excluding cost sharing reimbursements of research and development costs. Cost Sharing Reimbursements Cost sharing reimbursements, net Reimbursements earned by the entity for costs incurred under collaborative research and development agreements are recognized as cost sharing revenue in the period in which the related research and development costs are incurred. Reimbursements by the entity for agreed-upon costs incurred by partners under collaborative research and development agreements are recognized as a reduction in cost sharing revenue in the period in which the related research and development costs are incurred. Collaborative Revenues The aggregate revenue earned under collaborative research and development agreements. Total collaboration revenues Total revenues Total Revenues Total aggregate revenue earned under collaborative research and development agreements and grants. The increase (decrease) during the reporting period in collaboration payable. Collaboration payable Increase (Decrease) in Collaboration Payable Increase (Decrease) Accrued Contract and Research Costs Accrued contract research costs The increase (decrease) during the reporting period in accrued contract research costs. Other Accrued Liabilities Disclosure Text Block Other Accrued Liabilities The disclosure for accrued liabilities at the end of the reporting period, excluding accrued contract research costs. License and Development Agreements Collaborative Development, Commercialization and License Agreement with GSK Collaborative Arrangement Second Disclosure [Text Block] Collaborative Development, Commercialization and License Agreement with GSK The entire disclosure for second collaborative arrangements in which the entity is a participant, including a) information about the nature and purpose of such arrangements; b) its rights and obligations there under; c) the accounting policy for collaborative arrangements; and d) the income statement classification and amounts attributable to transactions arising from the collaborative arrangement between participants. Document and Entity Information Condensed Consolidated Balance Sheets Statement [Table] Statement, Scenario [Axis] Scenario, Unspecified [Domain] Statement [Line Items] Statement Assets [Abstract] Assets Assets, Current [Abstract] Current assets: Cash and Cash Equivalents, at Carrying Value Cash and cash equivalents Cash and cash equivalents at beginning of period Cash and cash equivalents at end of period Prepaid Expense and Other Assets, Current Prepaid expenses and other current assets Assets, Current Total current assets Available-for-sale Securities, Current Marketable securities Receivables, Long-term Contracts or Programs Collaboration receivable Property, Plant and Equipment, Net Property and equipment, net Assets Total assets Other Assets, Noncurrent Other assets Liabilities and Equity [Abstract] Liabilities and Stockholders' Equity Liabilities, Current [Abstract] Current liabilities: Accounts Payable, Current Accounts payable Capital Lease Obligations, Current Capital lease obligations Liabilities, Current Total current liabilities Secured Debt, Current Current portion of term loans Deferred collaboration revenue Deferred Revenue, Current Liabilities Total liabilities Preferred Stock, Value, Issued Preferred stock, par value $0.0001 per share Authorized: 5,000,000 shares at September 30, 2011 and December 31, 2010; no shares issued and outstanding at September 30, 2011 and December 31, 2010 Common Stock, Value, Issued Common stock, par value $0.0001 per share Authorized: 100,000,000 shares at September 30, 2011 and December 31, 2010; 49,498,350 and 42,090,205 shares issued and outstanding at September 30, 2011 and December 31, 2010, respectively Accumulated Other Comprehensive Income (Loss), Net of Tax Accumulated other comprehensive income (loss) Retained Earnings (Accumulated Deficit) Accumulated deficit Additional Paid in Capital, Common Stock Additional paid-in-capital Liabilities and Equity Total liabilities and stockholders' equity Liabilities, Noncurrent [Abstract] Long-term liabilities: Capital Lease Obligations, Noncurrent Capital lease obligations Deferred Revenue, Noncurrent Deferred collaboration revenue Secured Long-term Debt, Noncurrent Term loans, net of current portion Liabilities, Noncurrent Total long-term liabilities 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 or Stated Value Per Share Common stock, par value (in dollars 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 Preferred Stock, Par or Stated Value Per Share Preferred stock, par value (in dollars per share) Operating expenses: Costs and Expenses [Abstract] General and Administrative Expense General and administrative Restructuring Charges Restructuring Operating Expenses Total operating expenses Research and Development Expense (Excluding Acquired in Process Cost) Research and development Earnings Per Share [Abstract] Net loss per common share: Earnings Per Share, Basic Basic net loss per common share (in dollars per share) Earnings Per Share, Diluted Diluted net loss per common share (in dollars per share) Earnings Per Share, Basic and Diluted Basic and diluted net loss per common share (in dollars per share) Weighted Average Number of Shares Outstanding, Diluted [Abstract] Weighted-average common shares outstanding: Weighted Average Number of Shares Outstanding, Diluted Diluted weighted average number of common shares outstanding (in shares) Weighted Average Number of Shares Outstanding, Basic Basic weighted average number of common shares outstanding (in shares) Other Nonoperating Income (Expense) [Abstract] Other (expense) income: Other Nonoperating Income (Expense) Other (expense) income, net Operating Income (Loss) Loss from operations Revenue, Net [Abstract] Revenues: Grant revenues Revenue from Grants Interest Income (Expense), Nonoperating, Net Interest expense, net Condensed Consolidated Statements of Operations Adjustments to Reconcile Net Income (Loss) to Cash Provided by (Used in) Operating Activities [Abstract] Adjustments to reconcile net loss to net cash used in operating activities: Share-based Compensation Stock-based compensation expense Depreciation, Depletion and Amortization Depreciation and amortization Increase (Decrease) in Operating Capital [Abstract] Changes in operating assets and liabilities: Increase (Decrease) in Restricted Cash for Operating Activities Restricted cash Increase (Decrease) in Prepaid Expense and Other Assets Prepaid expenses and other current assets Increase (Decrease) in Other Accrued Liabilities Other accrued liabilities Increase (Decrease) in Deferred Revenue Deferred collaboration revenue Increase (Decrease) in Receivables Collaboration receivable Accounts payable Increase (Decrease) in Accounts Payable, Trade Increase (Decrease) in Other Noncurrent Assets Other assets Payments to Acquire Property, Plant, and Equipment Purchases of property and equipment Payments to Acquire Available-for-sale Securities Purchases of marketable securities Proceeds from Maturities, Prepayments and Calls of Available-for-sale Securities Maturities of marketable securities Proceeds from Issuance of Secured Debt Proceeds from term loans Proceeds from issuance of common stock and exercise of common stock options, net of transaction costs Proceeds from Issuance or Sale of Equity Payment of term loans Repayments of Secured Debt Repayments of Long-term Capital Lease Obligations Payment of capital lease obligations Cash Flow, Noncash Investing and Financing Activities Disclosure [Abstract] Supplemental disclosure of noncash operating, investing and financing activities: Acquisition of equipment under capital leases Capital Expenditures Incurred but Not yet Paid Supplemental Cash Flow Information [Abstract] Supplemental disclosure of cash flow information: Interest Paid Cash paid for interest Condensed Consolidated Statements of Cash Flows Nature of Business Nature of Operations [Text Block] Nature of Business Summary of Significant Accounting Policies Organization, Consolidation, Basis of Presentation, Business Description and Accounting Policies [Text Block] Summary of Significant Accounting Policies Cash, Cash Equivalents and Marketable Securities Cash, Cash Equivalents and Marketable Securities Cash, Cash Equivalents, and Marketable Securities [Text Block] Fair Value Measurements Fair Value Disclosures [Text Block] Fair Value Measurements Property and Equipment Property, Plant and Equipment Disclosure [Text Block] Property and Equipment Stockholders' Equity Stockholders' Equity Note Disclosure [Text Block] Stockholders' Equity Stock-Based Compensation Disclosure of Compensation Related Costs, Share-based Payments [Text Block] Stock-Based Compensation Other Accrued Liabilities Accounts Payable and Accrued Liabilities Disclosure [Text Block] Other Accrued Liabilities Collaborative Arrangement Disclosure [Text Block] License and Development Agreements Term Loans Debt Disclosure [Text Block] Term Loans Subsequent Event-Equity Line of Credit Subsequent Events [Text Block] Subsequent Event-Equity Line of Credit Entity Registrant Name Entity Central Index Key Document Type Document Period End Date Amendment Flag Amendment Description 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 Document Fiscal Year Focus Document Fiscal Period Focus Stockholders' equity: Stockholders' Equity Attributable to Parent [Abstract] Total stockholders' equity Stockholders' Equity Attributable to Parent Net loss Net loss Net Income (Loss) Available to Common Stockholders, Basic Cash flows from operating activities: Net Cash Provided by (Used in) Operating Activities, Continuing Operations [Abstract] Net cash used in operating activities Net Cash Provided by (Used in) Operating Activities, Continuing Operations Cash flows from investing activities: Net Cash Provided by (Used in) Investing Activities, Continuing Operations [Abstract] Net cash used in investing activities Net Cash Provided by (Used in) Investing Activities, Continuing Operations Cash flows from financing activities: Net Cash Provided by (Used in) Financing Activities, Continuing Operations [Abstract] Net cash provided by financing activities Net Cash Provided by (Used in) Financing Activities, Continuing Operations Net decrease in cash and cash equivalents Net Cash Provided by (Used in) Continuing Operations