Revenue - Summary of Sales from Contracts with Customers Disaggregated by Categories (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Disaggregation of Revenue [Line Items]
Revenues	$ 6,324	$ 4,505	$ 13,164	$ 9,939
Fixed-price
Disaggregation of Revenue [Line Items]
Revenues	873	1,066	1,688	2,025
Cost-plus
Disaggregation of Revenue [Line Items]
Revenues	3,925	2,758	8,215	6,191
Time and Material
Disaggregation of Revenue [Line Items]
Revenues	1,526	681	3,261	1,723
Related party
Disaggregation of Revenue [Line Items]
Revenues	6,268	4,493	13,093	9,891
Commercial
Disaggregation of Revenue [Line Items]
Revenues	$ 56	$ 12	$ 71	$ 48