Stock-Based Compensation - Summary of Stock-Based Compensation Expense for Stock Options Granted that was Recorded in the Company's Results of Operations (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Stock-based compensation expense
Stock-based compensation expense	$ 5,437	$ 9,768	$ 4,705
Cost of Product Revenue [Member]
Stock-based compensation expense
Stock-based compensation expense	365	803	125
Research and Development [Member]
Stock-based compensation expense
Stock-based compensation expense	1,184	1,603	1,384
Selling, General and Administrative [Member]
Stock-based compensation expense
Stock-based compensation expense	$ 3,888	$ 7,362	$ 3,196