Income Taxes - Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Deferred tax assets:
Net operating losses	$ 18,771	$ 14,800
Capitalized inventory costs	12,378	6,717
Stock based compensation	6,955	6,460
Accruals not currently deductible	4,883	6,157
Unrealized foreign exchange losses, net	3,087	3,013
Foreign tax credits	3,269	2,558
Other	1,871	599
Total deferred tax assets	51,214	40,304
Valuation allowance	(21,847)	(16,780)
Total deferred tax assets, net of allowances	29,367	23,524
Deferred tax liabilities:
Accelerated depreciation and amortization	(43,225)	(38,034)
Original issue discount on Convertible Notes due 2021	(8,553)	0
Tax on unremitted earnings	(8,555)	(7,181)
Other	(6,030)	(2,856)
Total deferred tax liabilities	(66,363)	(48,071)
Total net deferred tax liabilities	(36,996)	(24,547)
Non-current deferred tax assets	1,747	1,821
Non-current deferred tax liabilities	(38,743)	(26,368)
Net deferred tax liabilities	$ 36,996	$ 24,547