SHARE-BASED COMPENSATION EXPENSE -Recognition of Share-Based Compensation Expense (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Research and development expense	$ 650	$ 711
Total	76	117
Research and Development Expense [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Research and development expense	20	34
Research and Development Expense [Member] | Stock options [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Research and development expense	13	34
Research and Development Expense [Member] | Restricted Stock units [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Research and development expense	7	0
General and Administrative Expense [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
General and administrative expense	56	83
General and Administrative Expense [Member] | Stock options [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
General and administrative expense	34	53
General and Administrative Expense [Member] | Restricted Stock units [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
General and administrative expense	$ 22	$ 30