00100 - Statement - BALANCE SHEETS
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00200 - Statement - STATEMENTS OF OPERATIONS AND COMPREHENSIVE LOSS
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00200 - Statement - STATEMENTS OF OPERATIONS AND COMPREHENSIVE LOSS (calc 2)
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00400 - Statement - STATEMENTS OF CASH FLOWS
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40301 - Disclosure - Investments - Summary of Available-for-Sale Investments at Fair Value (Details)
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40401 - Disclosure - Property and Equipment - Net Property and Equipment at Cost (Details)
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40502 - Disclosure - Note Payable and Accrued Expenses - Schedule of Aggregate Future Minimum Payments Due Under Loan and Security Agreement (Details)
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40503 - Disclosure - Note Payable and Accrued Expenses - Accrued Expenses (Details)
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40801 - Disclosure - Common Stock Warrant and Option Exercises and Employee Stock Purchases (Details)
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40902 - Disclosure - Commitments and Contingencies - Future Minimum Commitments Under Lease Agreements (Details)
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41002 - Disclosure - Income Taxes - Components of the Deferred Tax Assets (Details)
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41003 - Disclosure - Income Taxes - Difference Between U.S. Federal Corporate Tax Rate and Company's Effective Tax Rate (Details)
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00090 - Document - Document and Entity Information
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00105 - Statement - BALANCE SHEETS (Parenthetical)
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00300 - Statement - STATEMENTS OF STOCKHOLDERS' EQUITY
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10101 - Disclosure - Organization
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10201 - Disclosure - Summary of Significant Accounting Policies
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10301 - Disclosure - Investments
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10401 - Disclosure - Property and Equipment
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10501 - Disclosure - Note Payable and Accrued Expenses
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10601 - Disclosure - Collaboration and License Agreements
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10701 - Disclosure - Stockholders' Equity
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10801 - Disclosure - Common Stock Warrant and Option Exercises and Employee Stock Purchases
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10901 - Disclosure - Commitments and Contingencies
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11001 - Disclosure - Income Taxes
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11101 - Disclosure - Employee Benefit Plan
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11201 - Disclosure - Net Loss per Common Share Applicable to Common Stockholders
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11301 - Disclosure - Supplemental Disclosure of Cash Flow Information
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11401 - Disclosure - April 2013 Pillar Agreements
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11501 - Disclosure - Financings
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11601 - Disclosure - Subsequent Event
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20202 - Disclosure - Summary of Significant Accounting Policies (Policies)
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30203 - Disclosure - Summary of Significant Accounting Policies (Tables)
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30303 - Disclosure - Investments (Tables)
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30403 - Disclosure - Property and Equipment (Tables)
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30503 - Disclosure - Note Payable and Accrued Expenses (Tables)
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30703 - Disclosure - Stockholders' Equity (Tables)
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30803 - Disclosure - Common Stock Warrant and Option Exercises and Employee Stock Purchases (Tables)
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30903 - Disclosure - Commitments and Contingencies (Tables)
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31003 - Disclosure - Income Taxes (Tables)
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31303 - Disclosure - Supplemental Disclosure of Cash Flow Information (Tables)
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31403 - Disclosure - April 2013 Pillar Agreements (Tables)
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40101 - Disclosure - Organization (Details)
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40201 - Disclosure - Summary of Significant Accounting Policies - Additional Information (Details)
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40202 - Disclosure - Summary of Significant Accounting Policies - Royalties (Details)
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40203 - Disclosure - Summary of Significant Accounting Policies - Change in Accumulated Balance of the Component of Other Comprehensive Loss (Details)
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40204 - Disclosure - Summary of Significant Accounting Policies - Schedule of Assumptions Used to Determine Fair Value of Stock Options Granted During Period (Details)
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40205 - Disclosure - Summary of Significant Accounting Policies - Assets and Liabilities Measured at Fair Value on a Recurring Basis (Details)
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40302 - Disclosure - Investments - Additional Information (Details)
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40402 - Disclosure - Property and Equipment - Additional Information (Details)
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40501 - Disclosure - Note Payable and Accrued Expenses - Additional Information (Details)
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40601 - Disclosure - Collaboration and License Agreements (Details)
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40701 - Disclosure - Stockholders' Equity - Common Stock (Details)
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40702 - Disclosure - Stockholders' Equity - Warrants Outstanding and Exercisable for the Purchase of Common Stock (Details)
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40703 - Disclosure - Stockholders' Equity - Stock Options (Details)
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40704 - Disclosure - Stockholders' Equity - Summary of Stock Options (Details)
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40705 - Disclosure - Stockholders' Equity - Employee Stock Purchase Plan (Details)
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40706 - Disclosure - Stockholders' Equity - Preferred Stock (Details)
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40901 - Disclosure - Commitments and Contingencies - Rent Expense and Lease Information (Details)
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40903 - Disclosure - Commitments and Contingencies - External Collaborations and Contract Obligations (Details)
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40904 - Disclosure - Commitments and Contingencies - Related-Party Transactions (Details)
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41001 - Disclosure - Income Taxes - Additional Information (Details)
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41101 - Disclosure - Employee Benefit Plan - Additional Information (Details)
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41201 - Disclosure - Net Loss per Common Share Applicable to Common Stockholders (Details)
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41301 - Disclosure - Supplemental Disclosure of Cash Flow Information (Details)
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41401 - Disclosure - April 2013 Pillar Agreements - Additional Information (Details)
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41402 - Disclosure - April 2013 Pillar Agreements - Schedule of Assumptions and Other Inputs Used to Compute Fair Value of Agreement Warrants (Details)
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41501 - Disclosure - Financings - October 2016 Follow-on Underwritten Public Offering (Details)
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41502 - Disclosure - Financings - February 2015 Follow-on Underwritten Public Offering (Details)
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41503 - Disclosure - Financings - February 2014 Follow-on Underwritten Public Offering (Details)
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