Reverse Recapitalization (Tables)

12 Months Ended

Dec. 31, 2020

Reverse Recapitalization [Abstract]

Business Combination, Separately Recognized Transactions [Table Text Block]

Cash - TortoiseCorp’s trust and cash (net of redemption)	$	236,484
Cash - PIPE		307,500
Cash - forward purchase units		17,500
Less: transaction costs and advisory fees paid		(45,030	)
Net Business Combination and PIPE financing	$	516,454

Business Combination, Segment Allocation [Table Text Block]

Common stock, outstanding prior to Business Combination	23,300,917
Less: redemption of TortoiseCorp shares	(3,308	)
Common stock of TortoiseCorp	23,297,609
TortoiseCorp founder shares	5,825,230
Shares issued in PIPE	30,750,000
Shares issued in connection with forward purchase agreement	1,750,000
Business Combination, PIPE, and forward purchase agreement financing shares	61,622,839
Legacy Hyliion shares(1)	92,278,990
Total shares of common stock immediately after Business Combination	153,901,829
Hyliion Holdings Corp. exercise of warrants	15,414,592
Total shares of common stock at December 31, 2020	169,316,421

Schedule of Legacy Hyliion shares

	Legacy Hyliion shares		Legacy Hyliion shares, effected for Exchange Ratio
Balance at December 31, 2018		24,453,750		35,634,061
Recapitalization applied to Series A outstanding at December 31, 2018		34,799,813		50,710,369
Exercise of common stock options - 2019		286,874		418,033
Exercise of common stock options - 2020 (pre-Closing)		763,216		1,112,160
Conversion of convertible notes payable to common stock(2)		2,336,235		4,404,367
				92,278,990