Business combinations

12 Months Ended

Dec. 31, 2016

Business Combinations [Abstract]

Business combinations

11. Business combinations

On June 30, 2014, the Company completed its acquisition of Pregenen, a privately-held biotechnology company, upon which Pregenen became a wholly-owned subsidiary. As a result, the Company obtained gene editing and cell signaling technology with a broad range of potential therapeutic applications. The Company considered the intangible asset acquired to be developed technology, as at the date of the acquisition it could be used the way it is intended to be used in certain ongoing research and development activities. From the date of acquisition, the gene editing platform intangible asset will be amortized to research and development expense over its expected useful life of approximately eight years.

Amortization expense for the gene editing platform intangible asset was $3.8 million and $3.8 million for the years ended December 31, 2016 and 2015, respectively, and accumulated amortization as of December 31, 2016 and 2015 was $9.4million and $5.6 million, respectively. The estimated amortization of intangible assets for the year ended December 31, 2016 and for each of the five succeeding years and thereafter is as follows (in thousands):

2017	$	3,763
2018		3,763
2019		3,763
2020		3,763
2021		3,763
2022		1,879
Total	$	20,694