Details of Selected Balance Sheet Accounts - Accounts Receivable (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Accounts receivable, net:
Accounts receivable	$ 99,746	$ 70,599
Allowance for doubtful accounts	(253)	(376)
Total accounts receivable, net	99,493	70,223
Trade
Accounts receivable, net:
Accounts receivable	76,370	48,875
Unbilled revenue
Accounts receivable, net:
Accounts receivable	23,041	21,169
Other
Accounts receivable, net:
Accounts receivable	$ 335	$ 555