Schedule II Valuation and Qualifying Accounts (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Deferred tax valuation allowance
Valuation and Qualifying Accounts
Balance at Beginning of Year	$ 114,523	$ 63,278	$ 4,239
Charged to Expense	32,333	51,245	59,039
Deductions	0	0	0
Balance at End of Year	146,856	114,523	63,278
Allowance for sales returns
Valuation and Qualifying Accounts
Balance at Beginning of Year	15,261	17,391	18,176
Charged to Expense	117,040	174,864	169,398
Deductions	121,194	176,994	170,183
Balance at End of Year	11,107	15,261	17,391
Allowance for doubtful accounts
Valuation and Qualifying Accounts
Balance at Beginning of Year	2,116	1,253	1,999
Charged to Expense	659	883	309
Deductions	301	20	1,055
Balance at End of Year	$ 2,474	$ 2,116	$ 1,253