Organization and Summary of Significant Accounting Policies - Additional Disclosures (Details) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Jan. 01, 2018	Dec. 31, 2015
Restricted Cash	$ 269,000	$ 424,000	$ 585,000
Cumulative Effect of New Accounting Principle in Period of Adoption		(3,365,000)
Deferred Costs	0	11,232,000
Deferred tax asset	13,937,000	6,317,000
Selling and Marketing Expense	36,065,000	32,702,000	26,744,000
Cash and cash equivalents	42,273,000	123,546,000	30,496,000
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents	42,542,000	123,970,000	31,081,000		$ 46,254,000
Restricted cash	269,000	424,000
Inventory impairments	10,000,000	2,200,000	3,500,000
Non-controlling interest in subsidiary	76,000	90,000
Equity Method Investment, Impairment Of Joint Ventures	28,776,000	0	0
Equity Method Investments, Impairment of Unconsolidated Entity Investments	18,900,000	0	0
Impairments related to investment in unconsolidated joint ventures		0	0
Allowance for doubtful contracts and accounts receivable	0	0
Depreciation and amortization	6,631,000	449,000	511,000
Other Depreciation and Amortization	$ 400,000	$ 400,000	500,000
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent	21.00%	35.00%
Noncash deferred tax asset charge	$ 0	$ 3,190,000	0
Defined Contribution Plan, Employer Matching Contribution, Percent of Match	50.00%
Defined Contribution Plan, Employer Matching Contribution, Percent of Employees' Gross Pay	8.00%
Defined Contribution Plan, Maximum Annual Contributions Per Employee, Amount	$ 11,000
Employer contribution amount	1,000,000	838,000	861,000
Capitalized Sales and Marketing Amortized	6,200,000	11,300,000	9,200,000
Stock Repurchased and Retired During Period, Value	8,500,000
Other than Temporary Impairment Losses, Investments	$ 1,100,000	0	$ 0
Typical Ownership Threshold [Member]
Equity Method Investment, Ownership Percentage	35.00%
Scenario, Forecast [Member]
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent	21.00%
Accounting Standards Update 2018-07 [Member]
Cumulative Effect of New Accounting Principle in Period of Adoption		$ 18,000
Accounting Standards Update 2014-09 [Member]
Selling and Marketing Expense	$ 100,000
Employee Stock Options and Restricted Stock Units [Member]
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized	2,600,000
Employee Stock Options and Restricted Stock Units [Member] | Consultant Stelmar [Member]
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized	$ 24,000
Common Stock [Member]
Stock Repurchased and Retired During Period, Shares	1,003,116
ASC 606 Adoption Other Assets Write Off [Member]
Deferred Costs				$ 4,700,000
Deferred tax asset				$ 1,300,000