Stockholders' equity (Tables)

12 Months Ended

Dec. 31, 2018

Stockholders' equity

Schedule of amount of shares of common stock reserved

	December 31,
	2018	2017
	(in thousands)
Outstanding stock options under the 2001 Plan	14	155
Outstanding stock options under the 2011 Plan	290	1,128
Outstanding RSUs under the 2011 Plan	3,119	3,324
Shares available for grant under the 2011 Plan	2,979	3,863
Total	6,402	8,470