Document and Entity Information [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 Accounts receivable from related party Accounts Receivable, Related Parties, Current Prepaid expenses and other current assets Prepaid Expense and Other Assets, Current Total current assets Assets, Current, Total Total current assets Property and equipment, net Property, Plant and Equipment, Net Long-term investments Long-term Investments Other assets Other Assets, Noncurrent Total assets Assets, Total Total assets Liabilities and Stockholders' Equity Liabilities and Equity [Abstract] Current liabilities: Liabilities, Current [Abstract] Accounts payable Accounts Payable, Current Accrued liabilities Accrued Liabilities, Current Deferred revenue from related party Deferred Revenue Current portion of equipment financing obligations Capital Lease Obligations, Current Total current liabilities Liabilities, Current, Total Total current liabilities Noncurrent equipment financing obligations Capital Lease Obligations, Noncurrent Deferred revenue from related party Due to Related Parties, Noncurrent Convertible note from related party Convertible Notes Payable, Noncurrent Other non-current liabilities Other Liabilities, Noncurrent Total liabilities Liabilities, Total Total liabilities Commitments Commitments and Contingencies Stockholders' equity: Stockholders' Equity Attributable to Parent [Abstract] Preferred stock: Preferred Stock, Number of Shares, Par Value and Other Disclosures [Abstract] Statement [Table] Class of Stock [Axis] Class of Stock [Domain] Preferred Stock [Member] Convertible Preferred Stock [Member] Statement [Line Items] Convertible preferred stock $0.001 par value; no shares and 48,989,914 shares authorized and issuable in Series A to E at March 31 2012 and December 31, 2011, respectively; no shares and 48,664,392 shares issued and outstanding; aggregate liquidation preference of $0 and $165,096 at March 31, 2012 and December 31, 2011, respectively; Convertible Preferred Stock, Nonredeemable or Redeemable, Issuer Option, Value Preferred stock, par value Preferred Stock, Par or Stated Value Per Share Preferred stock, shares authorized Preferred Stock, Shares Authorized Convertible Preferred Stock Shares Issuable Preferred stock, shares issuable in Series A to E Preferred stock, shares issuable in Series A to E Preferred stock, shares issued Preferred Stock, Shares Issued Preferred stock, shares outstanding Preferred Stock, Shares Outstanding Preferred stock, liquidation preference Preferred Stock, Liquidation Preference Per Share Other Preferred Stock [Member] Other Preferred Stock Other Preferred Stock Preferred stock, $0.001 par value, 10,000,000 shares authorized; no shares issued and outstanding; Preferred Stock, Value, Issued Common stock, $0.001 par value, 200,000,000 shares and 68,000,000 shares authorized at March 31, 2012 and December 31, 2011, respectively; 36,162,386 shares and 4,385,439 shares issued and outstanding at March 31, 2012 and December 31, 2011, respectively, net of shares subject to repurchase Common Stock, Value, Issued 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 Additional paid-in capital Additional Paid in Capital Employee note receivable Stockholders' Equity Note, Subscriptions Receivable Employee note receivable Accumulated other comprehensive loss Accumulated Other Comprehensive Income (Loss), Net of Tax Accumulated deficit Retained Earnings (Accumulated Deficit) Total stockholders' equity Stockholders' Equity Attributable to Parent, Total Total stockholders' equity Total liabilities and stockholders' equity Liabilities and Equity, Total Total liabilities and stockholders' equity Revenues: Revenues [Abstract] Collaborative research and development revenue from related party Revenue from Related Parties Operating expenses: Costs and Expenses [Abstract] Research and development Research and Development Expense General and administrative General and Administrative Expense Total operating expenses Costs and Expenses, Total Total operating expenses Loss from operations Operating Income (Loss) Loss from operations Interest income Investment Income, Interest Interest expense Interest Expense Interest expense Total interest income (expense), net Interest Income (Expense), Net, Total Total interest income (expense), net Net loss Net Income (Loss) Attributable to Parent Net loss Net loss per common share: Earnings Per Share [Abstract] Basic and Diluted Earnings Per Share, Basic and Diluted Shares used to compute net loss per common share: Weighted Average Number of Shares Outstanding, Diluted [Abstract] Weighted Average Number of Share Outstanding Basic and Diluted Basic and Diluted Basic and Diluted Consolidated net loss Increase/(decrease) in net unrealized gains on available-for-sale securities Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, Net of Tax Consolidated comprehensive loss Comprehensive Income (Loss), Net of Tax, Attributable to Parent Consolidated comprehensive loss Operating activities Net Cash Provided by (Used in) Operating Activities [Abstract] Adjustments to reconcile net loss to net cash provided by (used in) operating activities: Adjustments to Reconcile Net Income (Loss) to Cash Provided by (Used in) Operating Activities [Abstract] Depreciation of property and equipment Depreciation Stock-based compensation Share-based Compensation Noncash interest expense Other Noncash Expense Changes in assets and liabilities: Increase (Decrease) in Operating Capital [Abstract] Accounts receivable due from related party Increase (Decrease) in Accounts Receivable, Related Parties Accounts receivable due from related party Prepaids and other current assets Increase (Decrease) in Prepaid Expense and Other Assets Prepaids and other current assets Other assets Increase (Decrease) in Other Operating Assets Other assets Accounts payable Increase (Decrease) in Accounts Payable Other liabilities Increase (Decrease) in Other Operating Liabilities Deferred revenue Increase (Decrease) in Deferred Revenue Net cash (used in) provided by operating activities Net Cash Provided by (Used in) Operating Activities Net cash (used in) provided by operating activities Investing activities Net Cash Provided by (Used in) Investing Activities [Abstract] Purchases of property and equipment, net Payments to Acquire Property, Plant, and Equipment Purchases of property and equipment, net Purchase of investments Payments to Acquire Investments Purchase of investments Maturities of investments Proceeds from Sale, Maturity and Collection of Investments Net cash (used in) provided by investing activities Net Cash Provided by (Used in) Investing Activities Net cash (used in) provided by investing activities Financing activities Net Cash Provided by (Used in) Financing Activities [Abstract] Proceeds from equipment financing Proceeds from Long-term Capital Lease Obligations Payments on equipment financing obligations Repayments of Long-term Capital Lease Obligations Payments on equipment financing obligations Proceeds from exercise of stock options Proceeds from Stock Options Exercised Proceeds from exercise of warrants Proceeds from Warrant Exercises Proceeds from issuance of common stock Proceeds from Issuance of Common Stock Net cash provided by financing activities Net Cash Provided by (Used in) Financing Activities Net cash provided by financing activities Net increase (decrease) in cash and cash equivalents Cash and Cash Equivalents, Period Increase (Decrease) Net increase (decrease) in cash and cash equivalents Cash and cash equivalents at beginning of period Cash and cash equivalents at end of period Supplemental disclosures of cash flow information Supplemental Cash Flow Information [Abstract] Cash paid for interest Interest Paid Non-cash financing activity: Cash Flow, Noncash Investing and Financing Activities Disclosure [Abstract] Issuance of common stock for settlement of convertible debt, including accrued interest Stock Issued Description of Business Nature of Operations [Text Block] Description of Business [Abstract] Description of Business [Abstract] Summary of Significant Accounting Policies Significant Accounting Policies [Text Block] Summary of Significant Accounting Policies [Abstract] Summary of Significant Accounting Policies [Abstract] Cash Equivalents and Investments Cash, Cash Equivalents, and Marketable Securities [Text Block] Cash Equivalents and Investments [Abstract] Cash Equivalents and Investments [Abstract] Fair Value Measurements Fair Value Disclosures [Text Block] Fair Value Measurements [Abstract] Fair Value Measurements [Abstract] Convertible Preferred Stock Preferred Stock [Text Block] Convertible Preferred Stock [Abstract] Convertible Preferred Stock [Abstract] Related-Party Transactions Related Party Transactions Disclosure [Text Block] Related-Party Transactions [Abstract] Related-Party Transactions [Abstract] Equity Incentive Plans Disclosure of Compensation Related Costs, Share-based Payments [Text Block] Equity Incentive Plans [Abstract] Equity Incentive Plans [Abstract] Amendment Flag Current Fiscal Year End Date Document Period End Date Document Type Entity Central Index Key Entity Common Stock, Shares Outstanding Entity Filer Category Entity Registrant Name Document Fiscal Period Focus Document Fiscal Year Focus Condensed Consolidated Balance Sheets [Abstract] Condensed Consolidated Statements of Operations [Abstract] Condensed Consolidated Statement of Comprehensive Loss [Abstract] Condensed Consolidated Statements of Cash Flows [Abstract]