Intangible assets

9 Months Ended

Sep. 30, 2018

Intangible assets [Abstract]

Intangible assets

7.Intangible assets

During the three months ended September 30, 2018 and 2017, the Company recorded amortization expense for intangible assets of $3.9 million and $1.6 million, respectively. During the nine months ended September 30, 2018 and 2017, the Company recorded amortization expense for intangible assets of $11.7 million and $4.7 million, respectively. Amortization expense has been recorded in operating expenses, specifically selling, general and administrative and cost of product sales and contract manufacturing. As of September 30, 2018, the weighted average amortization period remaining for intangible assets was 8.2 years.