Summary of significant accounting policies and basis of presentation (Tables)

3 Months Ended

Mar. 31, 2017

Accounting Policies [Abstract]

Estimated Useful Lives of Assets

Depreciation and amortization is calculated using the straight-line method over the estimated useful lives of the assets, which are as follows:

Asset	Estimated useful life
Building	40 years
Computer equipment and software	3 years
Office and laboratory equipment	2 -5 years
Leasehold improvements	Shorter of the useful life or remaining lease term