Share-Based Payments (Tables)

9 Months Ended

Sep. 30, 2019

Share-based Payment Arrangement [Abstract]

Schedule of share-based compensation expense

Share-based compensation expense is as follows, in thousands of dollars:

	Three Months ended September 30,				Nine Months ended September 30,
	2019		2018		2019		2018
	(unaudited)				(unaudited)
Research and development	$	680	$	469	$	1,954	$	1,421
Selling, general and administrative	3,234		2,128		9,269		6,879
Total	$	3,914	$	2,597	$	11,223	$	8,300

Summary of stock options and SAR activities

The following table summarizes stock option and SAR activities:

	Number of Options		Weighted- Average Exercise Price		Weighted- Average Remaining Contractual Term (in years)
Outstanding, December 31, 2018	3,916,963		$	19.98	7.10
Granted	867,135		$	36.63
Exercised	(97,403	)	$	13.23
Forfeited	(48,449	)	$	35.73
Outstanding, September 30, 2019 (unaudited)	4,638,246		$	23.07	6.91
As of December 31, 2018:
Vested and expected to vest	3,916,963		$	19.98	7.10
Exercisable	1,889,947		$	12.47	5.96
As of September 30, 2019:
Vested and expected to vest	4,638,246		$	23.07	6.91
Exercisable	2,595,276		$	15.52	5.73