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Subsequent events | 9 Months Ended
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Sep. 30, 2017
Subsequent Events [Abstract] |
Subsequent events | Subsequent events In October 2017, the Company announced that the Sunfish, a two-part clinical trial in pediatric and adult type 2 and type 3 spinal muscular atrophy initiated in the fourth quarter of 2016, had transitioned into the pivotal second part of its study. The achievement of this milestone triggered a $20.0 million payment to the Company from F. Hoffman-La Roche Ltd and Hoffman-La Roche Inc., which was recorded as collaboration revenue at time of achievement.

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- Definition The entire disclosure for significant events or transactions that occurred after the balance sheet date through the date the financial statements were issued or the date the financial statements were available to be issued. Examples include: the sale of a capital stock issue, purchase of a business, settlement of litigation, catastrophic loss, significant foreign exchange rate changes, loans to insiders or affiliates, and transactions not in the ordinary course of business. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 855 -URI http://asc.fasb.org/topic&trid=2122774 + Details
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