Organization and Summary of Significant Accounting Policies - Additional Disclosures (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Restricted cash	$ 424	$ 585
Inventory impairments	2,200	3,500	$ 0
Noncontrolling interest in subsidiary	90	101
Impairments related to investment in unconsolidated joint ventures	0	0	0
Allowance for doubtful contracts and accounts receivable	0	0
Depreciation and amortization	$ 449	511	473
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent	35.00%
Effective Income Tax Rate Reconciliation, Change in Enacted Tax Rate, Amount	$ 3,190	0	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
Employer contribution amount	$ 838	$ 861	$ 523
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%