Basis of Presentation - Additional Information (Detail) - USD ($)		3 Months Ended		9 Months Ended
	May 28, 2019	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018	Dec. 31, 2017
Significant Accounting Policies [Line Items]
Preferred stock, share outstanding		0		0		0
Cash and cash equivalents and restricted cash		$ 50,224,000	$ 58,584,000	$ 50,224,000	$ 58,584,000	$ 83,317,000	$ 78,385,000
Cashflow from operations				7,389,000	24,853,000
Deferred tax assets, valuation allowance		87,584,000		87,584,000
Restricted cash		10,359,000		10,359,000		$ 10,565,000
Lower of cost or market inventory adjustment		0		0
Production cost		8,034,000	$ 7,231,000	22,380,000	$ 23,788,000
Written down of assets at salvage value		0		0
Impairment of long-lived assets				9,983,000
Other Operating Expenses
Significant Accounting Policies [Line Items]
Inventory write off				531,000
Impairment				8,101,000
Pic Onyx Inc
Significant Accounting Policies [Line Items]
Minority interest		4,300,000		4,300,000
Gain (loss) recorded at inception	$ 0
Exchange for convertible promissory note	$ 500,000
Convertible promissory note interest	7.50%
Convertible promissory maturing date	Aug. 01, 2021
Preferred stock voting percentage	22.00%
Non-cash change in property, plant and equipment and Intangible and other assets, net		3,500,000		3,500,000
Non-cash change in accounts payable and intangible and other assets, net		$ 400,000		$ 400,000
Pic Onyx Inc | Convertible Preferred Stock
Significant Accounting Policies [Line Items]
Preferred stock, share outstanding	9,700,000
Eufaula and Alabama
Significant Accounting Policies [Line Items]
Percentage of value of assets of project on construction in progress				87.00%
Projects completed percentage				75.00%