Selling, general and administrative expenses (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Selling, General and Administrative Expense [Abstract]
Personnel expenses	$ 22,461	$ 28,299	$ 49,382	$ 59,491
Share-based compensation	14,752	18,615	32,509	36,028
Travel expenses	1,487	4,605	5,280	8,859
Professional services	5,814	5,115	11,503	11,339
Office expenses	3,082	3,296	6,482	6,795
Other expenses	5,317	4,613	12,341	8,904
Total selling, general and administrative expenses	$ 52,913	$ 64,543	$ 117,497	$ 131,416

Amount of expense for award under share-based payment arrangement. Excludes amount capitalized.

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Amount of expense for salary, wage, profit sharing; incentive and equity-based compensation; and other employee benefit.

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Amount of general expenses not normally included in Other Operating Costs and Expenses.

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Amount of selling, general and administrative expense classified as other.

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A fee charged for services from professionals such as doctors, lawyers and accountants. The term is often expanded to include other professions, for example, pharmacists charging to maintain a medicinal profile of a client or customer.

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The aggregate total costs related to selling a firm's product and services, as well as all other general and administrative expenses. Direct selling expenses (for example, credit, warranty, and advertising) are expenses that can be directly linked to the sale of specific products. Indirect selling expenses are expenses that cannot be directly linked to the sale of specific products, for example telephone expenses, Internet, and postal charges. General and administrative expenses include salaries of non-sales personnel, rent, utilities, communication, etc.

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Expenses incurred for travel and entertainment during the period.

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