Net Income per Share - Basic and Diluted (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Earnings Per Share [Abstract]
Net income	$ 6,609	$ 8,528	$ 15,583	$ 15,554
Weighted Average Number of Shares Outstanding, Basic [Abstract]
Weighted-average shares of common stock outstanding	31,888	31,343	31,763	31,359
Shares used in computing basic net income per share	31,888	31,343	31,763	31,359
Incremental Weighted Average Shares Attributable to Dilutive Effect [Abstract]
Restricted stock subject to vesting	265	495	401	558
Shares issuable for acquisition consideration (in shares)	224	202	203	249
Shares issuable for conversion of convertible senior notes (in shares)	0		77
Shares used in computing diluted net income per share	32,377	32,040	32,444	32,166
Basic net income per share (in dollars per share)	$ 0.21	$ 0.27	$ 0.49	$ 0.50
Diluted net income per share (in dollars per share)	$ 0.20	$ 0.27	$ 0.48	$ 0.48