Shareholders' Equity - Share-Based Compensation Expense (Detail) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total share-based compensation expense	$ 519	$ 678
Per basic share	$ 0.04	$ 0.05
Per diluted share	$ 0.04	$ 0.05
Cost of revenue- professional engineering service [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total share-based compensation expense	$ 1	$ 28
Selling, general and administrative [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total share-based compensation expense	546	460
Research and development [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total share-based compensation expense	$ (28)	$ 190