SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES Narrative (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017	Mar. 31, 2018	Jan. 01, 2018	Dec. 31, 2017	Jul. 21, 2014
Significant Accounting Policies [Line Items]
Stockholders' Equity Attributable to Parent	$ 296,252		$ 296,252				$ 307,518
Inventory Valuation Reserves	1,100		1,100				900
Convertible senior notes, net of discount	$ 21,524		$ 21,524				138,998
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	3,714,000	3,062,000	3,714,000	3,062,000
Retained Earnings (Accumulated Deficit)	$ (131,221)		$ (131,221)			$ (116,429)	(115,433)
Convertible Debt [Member] | Convertible Senior 2019 Notes [Member]
Significant Accounting Policies [Line Items]
Fair value of convertible notes	$ 21,900		$ 21,900
Initial conversion price	$ 14.83		$ 14.83					$ 14.83
Convertible Debt Securities [Member]
Significant Accounting Policies [Line Items]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount			1,500,000
Difference between Revenue Guidance in Effect before and after Topic 606 | Accounting Standards Update 2014-09
Significant Accounting Policies [Line Items]
Retained Earnings (Accumulated Deficit)						(996)
Retained Earnings [Member]
Significant Accounting Policies [Line Items]
Stockholders' Equity Attributable to Parent	$ (131,221)		$ (131,221)				(115,433)
Retained Earnings [Member] | Difference between Revenue Guidance in Effect before and after Topic 606 | Accounting Standards Update 2014-09
Significant Accounting Policies [Line Items]
Retained Earnings (Accumulated Deficit)						$ (996)
Restatement Adjustment [Member]
Significant Accounting Policies [Line Items]
Stockholders' Equity Attributable to Parent							(3,494)
Restatement Adjustment [Member] | Retained Earnings [Member]
Significant Accounting Policies [Line Items]
Stockholders' Equity Attributable to Parent					$ 3,800		$ (3,494)