Net loss per share attributable to common stockholders (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Jul. 31, 2019
Numerator:
Net loss attributable to common stockholders, basic and diluted	$ (2,911)	$ (187)	$ (13,384)	$ (5,124)
Denominator:
Weighted average common stock, basic and diluted (in shares)	44,505	44,136	44,390	43,904
Net loss per share attributable to common stockholders:
Basic (in dollars per share)	$ (0.07)	$ 0.00	$ (0.30)	$ (0.12)
Diluted (in dollars per share)	$ (0.07)	$ 0.00	$ (0.30)	$ (0.12)
Maximum
Stock repurchase program
Stock repurchase amount					$ 20,000