Supplemental Balance Sheet Information - Allowance for Doubtful Accounts (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Allowance for doubtful accounts
Balance, beginning of period	$ 4,945	$ 1,033	$ 1,076
Additions	2,226	4,085	580
Write-offs	(884)	(173)	(623)
Balance, end of period	$ 6,287	$ 4,945	$ 1,033
Reserve for allowance for doubtful account	1.00%	1.00%	0.00%