0141 - Statement - Consolidated Statements of Cash Flows (Parenthetical) link:presentationLink link:calculationLink link:definitionLink 00 - Document - Document and Entity Information link:presentationLink link:definitionLink link:calculationLink 0110 - Statement - Consolidated Balance Sheets link:presentationLink link:definitionLink link:calculationLink 0111 - Statement - Consolidated Balance Sheets (Parenthetical) link:presentationLink link:definitionLink link:calculationLink 0120 - Statement - Consolidated Statements of Operations link:presentationLink link:definitionLink link:calculationLink 0130 - Statement - Consolidated Statements of Stockholders' Equity (Deficit) link:presentationLink link:definitionLink link:calculationLink 0140 - Statement - Consolidated Statements of Cash Flows link:presentationLink link:definitionLink link:calculationLink 0201 - Disclosure - Description of business and basis of presentation link:presentationLink link:definitionLink link:calculationLink 0202 - Disclosure - Summary of significant accounting policies link:presentationLink link:definitionLink link:calculationLink 0203 - Disclosure - Investment in securities link:presentationLink link:definitionLink link:calculationLink 0204 - Disclosure - State research and development credit exchange receivable link:presentationLink link:definitionLink link:calculationLink 0205 - Disclosure - Property and equipment link:presentationLink link:definitionLink link:calculationLink 0206 - Disclosure - Accrued expenses and other current liabilities link:presentationLink link:definitionLink link:calculationLink 0207 - Disclosure - Related-party loan arrangement link:presentationLink link:definitionLink link:calculationLink 0208 - Disclosure - Senior convertible notes link:presentationLink link:definitionLink link:calculationLink 0209 - Disclosure - Restructuring charges link:presentationLink link:definitionLink link:calculationLink 0210 - Disclosure - Fair Value of Financial Instruments link:presentationLink link:definitionLink link:calculationLink 0211 - Disclosure - Common and preferred stock link:presentationLink link:definitionLink link:calculationLink 0212 - Disclosure - Net loss per common share link:presentationLink link:definitionLink link:calculationLink 0213 - Disclosure - Stock award plans link:presentationLink link:definitionLink link:calculationLink 0214 - Disclosure - Commitments and contingencies link:presentationLink link:definitionLink link:calculationLink 0215 - Disclosure - Employee benefit plans link:presentationLink link:definitionLink link:calculationLink 0216 - Disclosure - Income taxes link:presentationLink link:definitionLink link:calculationLink 0217 - Disclosure - Related party transactions link:presentationLink link:definitionLink link:calculationLink 0218 - Disclosure - Selected quarterly financial data (unaudited) link:presentationLink link:definitionLink link:calculationLink 0219 - Disclosure - Subsequent events link:presentationLink link:definitionLink link:calculationLink