XML 29 R18.htm IDEA: XBRL DOCUMENT

Subsequent events	9 Months Ended
Subsequent events	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.