Summary of Significant Accounting Policies - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Jan. 01, 2019	Dec. 31, 2018
Significant Accounting Policies [Line Items]
Entity Incorporation Date Of Incorporation	Jan. 11, 1991
Options and warrants excluded from the calculation of diluted shares	4,673,897	2,948,848
Production and importation permission description	22 million pounds in 2015 and was reduced by approximately 4.5 million pounds each year ending at zero in 2020.
Revenue from Contract with Customer, Including Assessed Tax	$ 34,664	$ 42,428
Operating Loss Carryforwards	$ 37,400
Operating Loss Carryforwards, Limitations on Use	(subject to annual limitations of 80% of tax earnings) and $5.4 million expire through 2023 (subject to annual limitations of approximately $1.3 million).
Deferred Tax Assets, Valuation Allowance				$ 11,300
Concentration Risk, Customer	there was one customer accounting for 15% of the Company’s revenues.	there was one customer accounting for 11% of the Company’s revenues.
Operating Lease, Liability	$ 7,583
Valuation Allowance, Deferred Tax Asset, Increase (Decrease), Amount	13,300
No Expiration [Member]
Significant Accounting Policies [Line Items]
Operating Loss Carryforwards	32,000
State and Local Jurisdiction [Member]
Significant Accounting Policies [Line Items]
Operating Loss Carryforwards	22,000
Accounting Standards Update 2016-09 [Member]
Significant Accounting Policies [Line Items]
Operating Lease, Liability			$ 8,100
Financial Service [Member]
Significant Accounting Policies [Line Items]
Revenue from Contract with Customer, Including Assessed Tax	600	$ 600
Customer
Significant Accounting Policies [Line Items]
Accounts Receivable, net	$ 3,000	$ 4,000