Investments - Schedule of investments (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2018	Dec. 31, 2017
Disclosure of joint ventures [line items]
Investments, beginning balance	$ 681	$ 1,185
Equity in earnings (loss) of investment in joint venture and associates	(1,154)	201
Investments, ending balance	13,994	681
Weichai Ballard JV
Disclosure of joint ventures [line items]
Investments, beginning balance	0
Capital contribution to JV	14,286	0
Incorporation costs	320	0
Equity in earnings (loss) of investment in joint venture and associates	(617)	0
Investments, ending balance	13,989	0
Synergy Ballard JVCo
Disclosure of joint ventures [line items]
Investments, beginning balance	676	1,185
Adjustment for actual cash contributed to JV	0	(34)
Elimination of 10% profit on MEAs not yet sold or consumed	(139)	(676)
Capital contribution to JV		972
Equity in earnings (loss) of investment in joint venture and associates	(537)	201
Investments, ending balance	0	676
Other
Disclosure of joint ventures [line items]
Investments, beginning balance	5
Investments, ending balance	$ 5	$ 5

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Elimination of Ten Percent Profit on MEA Not Yet Sold Or Consumed

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Incorporation costs

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The aggregate cash flows used in obtaining control of subsidiaries or other businesses, classified as investing activities. [Refer: Subsidiaries [member]]

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Line items represent concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes of the table.

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The amount of investments accounted for using the equity method. The equity method is a method of accounting whereby the investment is initially recognised at cost and adjusted thereafter for the post-acquisition change in the investor's share of net assets of the investee. The investor's profit or loss includes its share of the profit or loss of the investee. The investor's other comprehensive income includes its share of the other comprehensive income of the investee. [Refer: At cost [member]]

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The entity's share of the profit (loss) of associates and joint ventures accounted for using the equity method. [Refer: Associates [member]; Investments accounted for using equity method; Joint ventures [member]; Profit (loss)]

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