Description of Business and Summary of Significant Accounting Policies - Summary of Allowance of Doubtful Accounts (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Allowance for Doubtful Accounts Receivable [Roll Forward]
Balance	$ 639	$ 608	$ 608
Provision for doubtful accounts	480	311	515
Uncollectible accounts written off, net of recovery	(544)	(280)	(515)
Balance	$ 575	$ 639	$ 608