Document and Entity Information [Abstract] Assets Assets [Abstract] Cash and Cash Equivalents, at Carrying Value Cash and cash equivalents at end of period Cash and cash equivalents at beginning of period Cash equivalents Cash and cash equivalents Short-term investments Short-term Investments Accounts receivable from related party Accounts Receivable, Related Parties, Current Prepaid Expense and Other Assets, Current Prepaid expenses and other 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 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 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 Commitments Commitments and Contingencies Stockholders' equity: Stockholders' Equity Attributable to Parent [Abstract] Preferred Stock, Number of Shares, Par Value and Other Disclosures [Abstract] The authorized, issued, and outstanding shares of convertible preferred stock Preferred stock: Statement [Table] Class of Stock [Axis] Class of Stock [Domain] Convertible Preferred Stock [Member] Convertible preferred stock Convertible preferred stock [Member] Statement [Line Items] Convertible Preferred Stock, Nonredeemable or Redeemable, Issuer Option, Value Convertible preferred stock $0.001 par value; no shares and 48,989,914 shares authorized and issuable in Series A to E at June 30, 2012 and December 31, 2011, respectively; no shares and 48,664,392 shares issued and outstanding at June 30, 2012 and December 31, 2011, respectively; aggregate liquidation preference of $0 and $165,096 at June 30, 2012 and December 31, 2011, respectively; Preferred stock, par value Preferred Stock, Par or Stated Value Per Share Preferred Stock, Shares Authorized Authorized Shares 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 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, Value, Issued Common stock, $0.001 par value, 200,000,000 shares and 68,000,000 shares authorized at June 30, 2012 and December 31, 2011, respectively; 36,171,295 shares and 4,385,439 shares issued and outstanding at June 30, 2012 and December 31, 2011, respectively, net of shares subject to repurchase Common Stock, Shares Authorized Common stock maximum under the Plan Common stock, shares authorized Common Stock, Shares, Issued Common stock, shares issued Additional paid-in capital Additional Paid in Capital Stockholders' Equity Note, Subscriptions Receivable Employee note receivable Accumulated Other Comprehensive Income (Loss), Net of Tax Accumulated other comprehensive loss Revenues [Abstract] Revenues from GSK Revenues: Operating expenses: Costs and Expenses [Abstract] Research and development Research and Development Expense General and administrative General and Administrative Expense Interest income Investment Income, Interest Interest Expense Interest expense Net Income (Loss) Attributable to Parent Net loss Consolidated net loss Net loss Earnings Per Share, Basic and Diluted Net loss Comprehensive Income (Loss), Net of Tax, Attributable to Parent Comprehensive loss Operating activities Net Cash Provided by (Used in) Operating Activities [Abstract] 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 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] Increase (Decrease) in Accounts Receivable, Related Parties Accounts receivable due from related party Increase (Decrease) in Prepaid Expense and Other Assets Prepaids and other current 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 Provided by (Used in) Operating Activities Net cash used in operating activities Investing activities Net Cash Provided by (Used in) Investing Activities [Abstract] Payments to Acquire Property, Plant, and Equipment Purchases of property and equipment, net Payments to Acquire Investments Purchase of investments Maturities of investments Proceeds from Sale, Maturity and Collection of Investments Financing activities Net Cash Provided by (Used in) Financing Activities [Abstract] Proceeds from equipment financing Proceeds from Long-term Capital Lease 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 Cash and Cash Equivalents, Period Increase (Decrease) Net decrease in cash and cash equivalents 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] Summary of Significant Accounting Policies Significant Accounting Policies [Text Block] Summary of Significant Accounting Policies [Abstract] Cash Equivalents and Investments Cash, Cash Equivalents, and Marketable Securities [Text Block] Cash Equivalents and Investments [Abstract] Fair Value Disclosures [Text Block] Fair Value Measurements Fair Value Measurements [Abstract] Preferred Stock [Text Block] Convertible Preferred Stock Convertible Preferred Stock [Abstract] Related Party Transactions Disclosure [Text Block] Related-Party Transactions Related-Party Transactions [Abstract] Disclosure of Compensation Related Costs, Share-based Payments [Text Block] Equity Incentive Plans 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] Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, Net of Tax Increase/(decrease) in net unrealized gains on available-for-sale securities Schedule of Anti Dilutive Securities Excluded from Computation of Earnings Per Share [Table Text Block] Company's potential common stock Fair Value Measurements, Recurring and Nonrecurring [Table Text Block] Fair value measurements of Company's financial assets and liabilities Schedule of Conversions of Stock [Table Text Block] The authorized, issued, and outstanding shares of convertible preferred stock Schedule of Related Party Transactions [Table Text Block] Revenues from GSK Available-for-sale Securities [Abstract] The amortized cost and fair value of cash and cash equivalents Available-for-sale Debt Securities, Amortized Cost Basis Amortized Cost Available-for-sale Securities, Gross Unrealized Gains Gross Unrealized Gains Available-for-sale Securities, Gross Unrealized Losses Gross Unrealized Losses Available-for-sale Securities, Fair Value Disclosure Fair Value Schedule of Available-for-sale Securities [Table] Major Types of Debt and Equity Securities [Axis] Major Types of Debt and Equity Securities [Domain] Money Market Funds [Member] Money market fund [Member] US Government-sponsored Enterprises Debt Securities [Member] Government-sponsored agencies [Member] Commercial Paper, Not Included with Cash and Cash Equivalents [Member] Commercial paper [Member] Corporate Debt Securities [Member] Corporate debt securities [Member] Schedule of Available-for-sale Securities [Line Items] Stock Split [Policy Text Block] Stock Split Stock split. Use of Estimates, Policy [Policy Text Block] Use of Estimates Description of Business (Textual) [Abstract] Description of Business (Textual) [Abstract] Description of business. Proceeds from Issuance Initial Public Offering Net proceeds after underwriting discounts, commissions and offering expenses Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Abstract] Fair value measurements of Company's financial assets and liabilities Commercial Paper [Member] Commercial paper [Member] Convertible Debt Securities [Member] Convertible debt from related party [Member] Fair Value, Liabilities Measured on Recurring Basis [Table Text Block] Change in fair market value of the Company's liabilities Financial Instruments, Financial Liabilities, Balance Sheet Groupings [Abstract] Change in fair market value of the Company's liabilities Liabilities, Fair Value Adjustment Change in fair market value prior to conversion Subsidiary or Equity Method Investee, Sale of Stock by Subsidiary or Equity Investee [Table] Subsidiary, Sale of Stock [Axis] Sale of Stock, Name of Transaction [Domain] IPO [Member] IPO [Member] Subsidiary, Sale of Stock [Line Items] Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number Shares, Options outstanding, Ending Balance Shares, Options outstanding, Beginning Balance Fair Value Measurements, Recurring and Nonrecurring [Table] Fair Value, Hierarchy [Axis] Fair Value, Measurements, Fair Value Hierarchy [Domain] Asset Class [Axis] Fair Value by Asset Class [Domain] Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] Fair Value Inputs, Liabilities, Quantitative Information [Table] Liability Class [Axis] Fair Value by Liability Class [Domain] Fair Value Inputs, Liabilities, Quantitative Information [Line Items] Fair Value Measurements (Textual) [Abstract] Fair Value Measurements (Textual) [Abstract] Fair value measurements. Convertible Debt, Fair Value Disclosures Estimated fair value of convertible debt Series A Preferred Stock [Member] Series A convertible preferred stock [Member] Series C Preferred Stock [Member] Series C convertible preferred stock [Member] Series D Preferred Stock [Member] Series D convertible preferred stock [Member] Series E Preferred Stock [Member] Series E convertible preferred stock [Member] Preferred Stock, Liquidation Preference, Value Aggregate Liquidation Preference Convertible Preferred Stock (Textual) [Abstract] Convertible Preferred Stock (Textual) [Abstract] Convertible preferred stock. Convertible Preferred Stock, Shares Issued upon Conversion Number of preferred stock converted into common stock Schedule of Stock by Class [Table] Class of Stock [Line Items] Contract Revenue [Member] Contract revenue. Contract revenue [Member] Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period Shares, Options outstanding, Exercised Share-based Compensation Arrangement by Share-based Payment Award, Options, Forfeitures and Expirations in Period Shares, Options outstanding, Cancelled Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price Weighted Average Exercise Price, Options outstanding, Ending Balances Weighted Average Exercise Price, Options outstanding, Beginning Balance Related Party Transactions (Additional Textual) [Abstract] Related-Party Transactions (Additional Textual) [Abstract] Related party transactions. Accounts Receivable, Related Parties Accounts receivable balance from GSK Deferred Revenue Arrangement By Type [Table] Deferred Revenue Arrangement Type [Axis] Deferred Revenue Arrangement [Line Items] Equity Incentive Plans (Textual) [Abstract] Equity incentive plans. Equity Incentive Plans (Textual) [Abstract] Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized Shares available for issuance under the Plan Common Stock, Capital Shares Reserved for Future Issuance Company's common stock reserved for issuance Share-based Compensation Arrangement by Share-based Payment Award, Non-Option Equity Instruments, Forfeitures and Expirations Common stock subject to outstanding awards under the Prior Plans Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Outstanding, Weighted Average Remaining Contractual Term Maximum vesting term granted with different vesting terms date of grant Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period Outstanding options vest Nineteen Ninety Seven Plan [Member] 1997 Plan [Member] Nineteen ninety seven plan. Two Thousand Twelve Plan [Member] 2012 Plan [Member] Two thousand twelve plan. Employee Stock Purchase Plan [Member] Employee stock purchase plan. Employee Stock Purchase Plan [Member] Shares Available For Issuance Under Plan Annual Increase Rate Shares available for issuance under Plan annual increase rate Shares available for issuance under plan annual increase rate. Exercise Prices Date Of Grant Fair Value Rate Exercise prices date of grant fair value rate Exercise prices date of grant fair value rate. Schedule of Share-based Compensation Arrangements by Share-based Payment Award [Table] Plan Name [Axis] Plan Name [Domain] Share-based Compensation Arrangement by Share-based Payment Award [Line Items] Convertible Debt Convertible loan principal amount Debt Instrument, Convertible, Effective Interest Rate Convertible loan interest rate Debt Instrument, Maturity Date Convertible loan maturity date Conversion price of common stock Debt Instrument, Convertible, Conversion Price Purchase Of Warrant Common Stock Purchase of warrant common stock. Purchase of warrant common stock Warrant Common Stock Exercise Price Warrant common stock exercise price. Warrant common stock exercise price Parties Purchased Common Stock Techne purchased common stock Parties purchased common stock. Parties Purchased Common Stock Per Share Techne purchased common stock per share Parties purchased common stock per share. Warrant Common Stock Exercise Price Rate Warrant common stock exercise price rate. Warrant common stock exercise price rate Defined Contribution Plan, Employers Matching Contribution, Annual Vesting Percentage Total grant vesting Cash Equivalents and Investments (Textual) [Abstract] Cash Equivalents and Investments (Textual) [Abstract] Cash equivalents and investments. Available For Sale Securities Unrealized Loss Position Fair Value Unrealized loss position Available for sale securities unrealized loss position fair value. Cash Equivalents and Investments (Additional Textual) [Abstract] Cash Equivalents and Investments (Additional Textual) [Abstract] Cash equivalents and investments. Available-for-sale Securities, Gross Unrealized Gain (Loss) Significant realized gains or losses on available-for-sale securities Available-for-sale Securities and Held-to-maturity Securities Available-for-sale securities held Range [Axis] Range [Domain] Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward] Option activity under its Stock Plans Assets, Current [Abstract] Current assets Liabilities, Current, Total Total current liabilities Liabilities, Total Total liabilities Stockholders' Equity Attributable to Parent, Total Total stockholders' equity Liabilities and Equity, Total Total liabilities and stockholders' equity Costs and Expenses, Total Total operating expenses Operating Income (Loss) Loss from operations Interest Income (Expense), Net, Total Total interest income (expense), net Net Cash Provided by (Used in) Investing Activities Net cash (used in) provided by investing activities Net Cash Provided by (Used in) Financing Activities Net cash provided by financing activities Deferred Revenue Arrangement Type [Domain] Glaxo Group [Member] Glaxo Group Limited [Member] Glaxo group limited. Parties to Contractual Arrangement [Axis] Parties to Contractual Arrangement [Domain] Earnings Per Share, Policy [Policy Text Block] Net Loss Per Share Sale of Stock, Price Per Share IPO price per share Stock Issued During Period, Shares, New Issues Shares issued Stock Option [Member] Options to purchase common stock [Member] Warrant [Member] Warrants to purchase common stock Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount Net Loss Per Share Fair Value, Inputs, Level 1 [Member] Level 1 [Member] Fair Value, Inputs, Level 2 [Member] Level 2 [Member] Fair Value, Inputs, Level 3 [Member] Level 3 [Member] Debt Conversion, Converted Instrument, Shares Issued Outstanding, accrued, unpaid interest converted into common stock Conversion of debt into common stock Preferred Stock Shares Issued and Outstanding Shares Issued and Outstanding Preferred stock shares issued and outstanding. Retained Earnings (Accumulated Deficit) Accumulated deficit Proceeds from Issuance of Private Placement Gross proceeds in concurrent private placements Preferred Stock, Shares Issued Preferred stock, shares issued Minimum [Member] Minimum [Member] Equity Incentive Plans (Additional Textual) [Abstract] Equity Incentive Plans (Additional Textual) [Abstract] Equity incentive plans. Assets, Fair Value Disclosure Total assets Liabilities, Fair Value Disclosure Balance as of June 30, 2012 Balance as of December31, 2011 Total liabilities Equity Unit Purchase Agreements [Member] Common stock subject to repurchase [Member] Weighted Average Number of Shares Outstanding, Basic and Diluted Shares used in computing basic and diluted loss per share amounts Dilutive Securities, Effect on Basic Earnings Per Share [Abstract] Company's potential common stock Series B Preferred Stock [Member] Series B Convertible Preferred Stock [Member] Series B convertible preferred stock [Member] Revenue from Related Parties Total revenues Collaborative research and development revenue from related party Up-front Payment Arrangement [Member] Recognition of up-front payments [Member] Cash Equivalents And Marketable Securities [Table Text Block] The amortized cost and fair value of cash and cash equivalents cash equivalents and marketable securities. Warrant Contractual Term Warrant contractual term. Warrant contractual term Common Stock, Shares, Outstanding Common stock subject to outstanding awards under the Plan Common stock, shares outstanding Schedule of Share-based Compensation, Stock Options, Activity [Table Text Block] Option activity under its Stock Plans Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross Shares, Options outstanding, Granted Company granted to employees options to purchase Share-based Compensation Arrangements by Share-based Payment Award, Options, Grants in Period, Weighted Average Exercise Price Weighted Average Exercise Price, Granted Share-based Compensation Arrangements by Share-based Payment Award, Options, Exercises in Period, Weighted Average Exercise Price Weighted Average Exercise Price, Exercised Share-based Compensation Arrangement by Share-based Payment Award, Options, Forfeitures and Expirations in Period, Weighted Average Exercise Price Weighted Average Exercise Price, Cancelled Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Remaining Contractual Term Shares, Options, Weighted Average Remaining Contractual Term Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Intrinsic Value Shares, Options, Aggregate Intrinsic Value Allocated Share-based Compensation Expense Unrecognized compensation expense related to employee stock options Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized, Period for Recognition Total unrecognized compensation expense related to employee stock options weighted-average period Common Stock, Par or Stated Value Per Share Common stock price Common stock, par value Investment Type [Axis] Investment Type Categorization [Domain] Two Thousand Two Plan [Member] 2002 Plan [Member] Two thousand two plan. Shares Available for Issuance Under Plan Annual Increase Share Shares available for issuance under Plan annual increase shares Shares available for issuance under plan annual increase share. Prior Plans [Member] Prior Plans [Member] Prior plans. Common Stock Initially Reserved for Issuance Common stock initially reserved for issuance. Common stock initially reserved for issuance Defined Contribution Plan Remaining Grant Vesting Remaining grant vesting Defined contribution plan remaining grant vesting. Related Party Transactions (Textual) [Abstract] Related party transactions. Related-Party Transactions (Textual) [Abstract] Schedule of Related Party Transactions, by Related Party [Table] Related Party [Axis] Related Party [Domain] Related Party Transaction [Line Items] February Two Thousand Twelve Techne Warrant [Member] Feb 2012 Techne warrant [Member] February two thousand twelve techne warrant. Private Placement [Member] Private Placement [Member] Other Nonoperating Income (Expense) [Abstract] Other income (expense):