Common Stock and Preferred Stock - Additional Information (Detail)		1 Months Ended		3 Months Ended
	Apr. 27, 2017 USD ($) shares	Jan. 31, 2018 USD ($) ExecutiveOfficers Director shares	Jun. 30, 2017 USD ($) shares	Mar. 31, 2018 USD ($)	Jun. 30, 2017 USD ($) shares	Mar. 31, 2017 USD ($) ExecutiveOfficers Director shares	Dec. 31, 2016 USD ($)
Class of Stock [Line Items]
Cash dividend paid				$ 0		$ 0
4.25% Convertible Senior Notes (due 2018)
Class of Stock [Line Items]
Amount of convertible notes repurchased and retired			$ 12,000,000		$ 12,000,000	$ 39,100,000	$ 6,100,000
Common Stock | 4.25% Convertible Senior Notes (due 2018)
Class of Stock [Line Items]
Common stock shares issued upon conversion of debt instrument | shares			112,400		112,400	2,865,000
Common stock shares issued upon conversion of debt instrument, value			$ 400,000			$ 15,100,000
Amount of convertible notes repurchased and retired			$ 11,600,000		$ 11,600,000	$ 39,100,000
Common Stock | Hong Kong Meisheng Cultural Co
Class of Stock [Line Items]
Common stock issued, shares | shares	3,660,891
Common stock issued, value	$ 19,300,000
Executive officer
Class of Stock [Line Items]
Restricted stock issued, shares | shares		1,914,894				873,787
Restricted stock issued, value		$ 4,500,000				$ 4,500,000
Number of executive officers | ExecutiveOfficers		2				2
Executive officer | Restricted Stock
Class of Stock [Line Items]
Vesting period						3 years
Non-employee directors
Class of Stock [Line Items]
Restricted stock issued, shares | shares		249,480				94,102
Restricted stock issued, value		$ 600,000				$ 500,000
Number of non-employee directors | Director		6				5
Non-employee directors | Hong Kong Meisheng Cultural Co
Class of Stock [Line Items]
Restricted stock issued, shares | shares	13,319
Restricted stock issued, value	$ 100,000
Non-employee directors | Restricted Stock
Class of Stock [Line Items]
Shares of restricted stock, vesting date		2019-01				2018-01
Non-employee directors | Restricted Stock | Hong Kong Meisheng Cultural Co
Class of Stock [Line Items]
Shares of restricted stock, vesting date	2018-01