XML 65 R45.htm IDEA: XBRL DOCUMENT v3.20.1
Fair Value of Financial Assets and Liabilities - Additional Information (Detail) - USD ($)
Aug. 02, 2019
Dec. 31, 2019
Dec. 31, 2018
May 02, 2017
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]        
Long-term debt, net   $ 40,176,000 $ 3,640,000  
Silicon Valley Bank [Member] | 2019 Term Loan [Member]        
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]        
Term loan, principal amount $ 40,000,000.0      
Long-term debt, net 40,000,000.0      
Silicon Valley Bank And MidCap Financial Funding XIII Trust [Member] | 2019 Term Loan [Member]        
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]        
Repayments of lines of credit $ 7,700,000      
2024 Convertible Notes [Member]        
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]        
Term loan, principal amount   $ 201,300,000   $ 201,300,000
Fair value of liability       136,700,000
Unamortized debt discount       $ 64,500,000
Debt instrument interest rate   3.375%   3.375%
Estimated fair value of Convertible Notes   $ 215,700,000