Summary of Significant Accounting Policies and Recent Accounting Pronouncements - Additional Information (Detail)	12 Months Ended
	Dec. 31, 2018 USD ($) Segment	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)	Jan. 01, 2019 USD ($)
Summary Of Significant Accounting Policies [Line Items]
Number of operating segments | Segment	1
Deferred revenue	$ 3,300,000
U.S. federal corporate tax rate	21.00%	34.00%	34.00%
Rent expense and occupancy costs	$ 7,900,000	$ 4,400,000	$ 5,600,000
Employee Stock Purchase Plan [Member]
Summary Of Significant Accounting Policies [Line Items]
Percentage of closing price of common stock	85.00%
Percentage of discount recognized on graded-vesting based on stock-based compensation expense over the purchase period	15.00%
Patents [Member]
Summary Of Significant Accounting Policies [Line Items]
Initial term of patents	20 years
Product Revenues [Member] | Customer One [Member]
Summary Of Significant Accounting Policies [Line Items]
Concentration of credit risk percentage	42.00%
Product Revenues [Member] | Customer Two [Member]
Summary Of Significant Accounting Policies [Line Items]
Concentration of credit risk percentage	38.00%
Product Revenues [Member] | Customer Three [Member]
Summary Of Significant Accounting Policies [Line Items]
Concentration of credit risk percentage	18.00%
Accounts Receivable [Member] | Customer One [Member]
Summary Of Significant Accounting Policies [Line Items]
Concentration of credit risk percentage	51.00%
Accounts Receivable [Member] | Customer Two [Member]
Summary Of Significant Accounting Policies [Line Items]
Concentration of credit risk percentage	28.00%
Accounts Receivable [Member] | Customer Three [Member]
Summary Of Significant Accounting Policies [Line Items]
Concentration of credit risk percentage	10.00%
Minimum [Member]
Summary Of Significant Accounting Policies [Line Items]
Accounts receivable payment term	30 days
Minimum [Member] | Subsequent Event [Member] | ASU No. 2016-02 [Member]
Summary Of Significant Accounting Policies [Line Items]
Right of use assets				$ 40,000,000
Lease liabilities				60,000,000
Maximum [Member]
Summary Of Significant Accounting Policies [Line Items]
Accounts receivable payment term	60 days
U.S. federal corporate tax rate		35.00%
Maximum [Member] | Subsequent Event [Member] | ASU No. 2016-02 [Member]
Summary Of Significant Accounting Policies [Line Items]
Right of use assets				45,000,000
Lease liabilities				$ 65,000,000
Outside of U.S. [Member] | Minimum [Member]
Summary Of Significant Accounting Policies [Line Items]
Accounts receivable payment term	60 days
Outside of U.S. [Member] | Maximum [Member]
Summary Of Significant Accounting Policies [Line Items]
Accounts receivable payment term	120 days