Convertible Senior Notes - Additional Information (Detail)		12 Months Ended
	May 24, 2016 USD ($) d $ / shares	Dec. 31, 2016 USD ($)
Debt Instrument [Line Items]
Proceeds from issuance of convertible senior notes, net of costs		$ 111,070,000
Accretion of the debt discount		$ 2,274,000
2.125% Convertible Senior Notes due 2021
Debt Instrument [Line Items]
Notes issued	$ 115,000,000
Notes, interest rate	2.125%	2.125%
Notes, frequency of periodic payment		Semi-annually
Notes, date of first required payment		Dec. 01, 2016
Notes, due date		Jun. 01, 2021
Notes conversion ratio per $1,000 principal amount	0.0311813
Notes initial conversion price | $ / shares	$ 32.07
Debt covenants debt default holder percent to declare all notes due minimum	25.00%
Number of days within which entity fails to satisfy obligations considered as event of default	270 days
Notes issued, fair value	$ 96,289,000
Contractual coupon interest		$ 1,473,000
Accretion of the debt discount		1,934,000
Amortization of the debt issuance costs		$ 340,000
Effective interest rate on the Notes		6.60%
Notes, carrying value		$ 95,272,000
Fair value of the note		$ 135,600,000
2.125% Convertible Senior Notes due 2021 | On any business day on or after June 5, 2019 and prior to the maturity date
Debt Instrument [Line Items]
Notes threshold percentage of stock price trigger	130.00%
Notes threshold trading days | d	20
Notes threshold consecutive trading days	30 days
Notes redemption price	100.00%