12 Expenses by nature

Operating expenses included the following costs by nature:

	Years ended December 31,
	2016		2015		2014
	in thousands
Employee-related expenses	$	42,260	$	31,398	$	27,685
Laboratory and development expenses		21,054		10,874		8,483
Legal and advisory expenses		11,715		12,209		8,137
Office and housing expenses		10,384		7,075		4,981
Patents and license expenses		1,348		1,342		1,181
Depreciation, amortization and impairment expenses		6,089		6,324		2,580
Non-employee share-based compensation expenses		670		6,429		4,087
Other operating expenses		4,989		6,857		3,711

Total	$	98,509	$	82,508	$	60,845

Details of employee-related expenses for the year ended December 31 are as follows:

	Years ended December 31,
	2016		2015		2014
	in thousands, except for employee numbers
Wages and salaries	$	24,999	$	19,274	$	15,640
Social security costs		1,824		1,440		1,257
Health insurance		1,099		828		348
Pension costs—defined contribution plans		1,088		608		804
Share-based compensation expenses		5,544		5,188		4,309
Consultant expenses		5,873		3,037		5,053
Other employee expenses		1,833		1,023		274

Total	$	42,260	$	31,398	$	27,685


Number of employees at the end of the period		251		198		162