Summary of Significant Accounting Policies - Summary (Details) - USD ($)		6 Months Ended
	Jan. 01, 2020	Jun. 30, 2020	Dec. 31, 2019	Jun. 30, 2019	Dec. 31, 2018
Restricted cash
Cash and cash equivalents		$ 266,974,000	$ 62,430,000
Restricted cash		9,326,000	9,326,000
cash, cash equivalents and restricted cash in the condensed consolidated statements of cash flows		276,300,000	71,756,000	$ 48,840,000	$ 38,596,000
Accounts Receivable
Allowance for doubtful accounts receivable		1,771,000	1,240,000
Bad debts write-offs		0
Inventory
Inventory write-down		7,400,000
Retained earnings		$ (283,662,000)	$ (189,710,000)
Adjustment | ASU 2016-13
Inventory
Retained earnings	$ 0
Adjustment | ASU 2018-15
Inventory
Costs capitalized relating to global enterprise systems	$ 1,600,000